\RT )E 75 7 DAYS lo Atlantic Continental Shelf and Slope of the United States | i*, Macrobenthic Invertebrate Fauna of the Middle Atlantic Bight Region- Faunal Composition and “11“er flismhfll‘mw p 9 IgH AVG 19 1981 LIBRARY UNIVERSITY OF CALIFORNIA GEOLOGICAL SURVEY PROFESSIONAL PAPER 529-N Atlantic Continental Shelf and Slope of the United States- Macrobenthic Invertebrate Fauna of the Middle Atlantic Bight Region-Faunal Composition and Quantitative Distribution By ROLAND L. WIGLEY ard ROGER B. THEROUX CEOLOGICAL SURVEY, PROFESSIONAL PAPER 529- N A description of the quantitative distribution of macrobenthic invertebrate animals in relation to geographic location, water depth, bottom sediments, and range in bottom water temperature UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1981 UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, Secretary GEOLOGICAL SURVEY Doyle G. Frederick, Acting Director Library of Congress Cataloging in Publication Data (Revised) United States. Geological Survey. Atlantic Continental Shelf and slope of the United States. (Geological Survey Professional paper; 529-N) Program conducted jointly by the U. S. Geological Survey and the Woods Hole Oceanographic Institution. Includes bibliographies. CONTENTS: A. Geologic background, by K. O. Emery.-B. Physiography and sediments of the deep-sea basin, by R. M. Pratt.-[etec.] -N. Macrobenthic invertebrate fauna of the Middle Atlantic bight region, by R. L. Wigley and R. B. Theroux. 1. Continental margins-United States. 2. Oceanography-Atlantic coast (United States). 3. Marine biology-Atlantic coast (United States). I. Woods Hole, Mass. Oceanographic Institution. II. Title. III. Series. QET5.P9 no. 529 557.3s [551.4'1] 79-604860 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page A DEUIACE .. .. .. .. .. .. .. .. ... .. .s s n m an he ua me ue ue me me moe oe e soe to he he oe me he m e bave e i ae Jupl 1 Reconnaissance Survey ______________________-_- 1 Middle Atlantic Bight region _______________--- 2 Previous studies _____________________________- 2 Materials and methods .........._______.__________._ 5 Macrofauna samples _________________________- 5 Benthos sampling gear _______________________- T Sample PrOCeSSINE 7 Data TreductiOM. 7T - L cl lol c sun onne nln ne me coven be ieee ue he foie be mane 10 'TTEeMBPETALUTE . 10 Creological SAMDICS 10 Faunal composition _____________________________-_- 10 Entire Middle Atlantic Bight region ___________- 10 Subarea differences in composition _____________- 17 Geographic distribution __________________________-- 18 Total macrobenthic fauna of all taxonomic groups 18 Major taxonomic components ___________________ 283 Selected genera and species ___________________-- 95 Phylum Annelida _______________________-- 95 Phylum Pogonophoro _____________________- 95 Phylum Mollusca ________________________- 95 Phylum Arthropoda ______________________- 95 Phylum Echinodermata ___________________- 101 Bathymetric distribution __________________________- 101 Total macrobenthic fauna of all taxonomic groups - 101 Entire Middle Atlantic Bight region _______ 101 SUDATCORE .. 106 Taxonomic ___________________________- 108 Entire Middle Atlantic Bight region ________ 108 ILLUSTRATIONS FIGURE 1. Chart of the Middle Atlantic Bight region showing the location of geographical features and the three subarea divisions: Southern New England, New York Bight, and Chesapeake Bight __ 2. Chart showing station locations where quantitative samples of macrobenthic invertebrates were obtained 8. Photograph showing side view of the Smith-McIntyre spring-loaded bottom sampler in the closed PORIION - .~ -. >» - o » » 2 meio ae ore m mene toe mome Photograph showing bottom view of Campbell grab sampler _______________________________- Pie charts illustrating the taxonomic composition of the total macrobenthic fauna in the entire Middle Atlantic Bight region _______. » ® III Page Relation to bottom sediments _____________________-- N124 Distribution of sediment types _______________-- 124 Total macrobenthic fauna of all taxonomic groups - 124 Entire Middle Atlantic Bight region ________ 124 SUHDATERE | as.. .. .. .. a a her s cei h mo a a me me me w mee the aes te te ese rete is 132 Taxonomic ...... = 137 Entire Middle Atlantic Bight region _______ 137 SUDATEAS | .. - = .. 2 o. s son oo oo so o n Hh he mn H Hh ae os ae me Te he oe ne he eee he an me oe in on 137 Relation to sediment organic carbon _______________- 137 Distribution of sediment organic carbon _______- 187 Total macrobenthic fauna of all taxonomic groups - 137 TaKXONOMHC TOUDE 3s = -. 1. -. ss ae. o. o. oo a co - oo hone neon ae me an me mse oe ie se 137 Entire Middle Atlantic Bight region ________ 187 Southern New England ________________---- 154 Relation to range in bottom water temperature _____. 154 Total macrobenthic fauna of all taxonomic groups - 166 Entire Middle Atlantic Bight region _______ 166 SUDATEORS . .. 2... . .. .. o. c cen so b mele h he mn halon se mae meme ue me mooi ie 170 Southern New England ______________-- 170 New York Bight _____________________- 170 Chesapeake Bight ....______________.. 170 Taxonomic ________________________ 170 Entire Middle Atlantic Bight region ____ _ 170 Subarea differences in distribution of taxonomic grOUps __________________- 170 Dominant faunal components _______________________ 192 Bays and SOUNUS ...: 192 Continental Shelf 192 Continental 192 Continental Rige 195 Acknowledgments aureus umn suk 195 References citéd 195 Page N3 ___________________________________________________ 6 ___________________________________________________ 8 9 ___________________________________________________ 12 IV FIGURE CONTENTS Page 6. Pie charts illustrating the taxonomic composition of the total macrobenthic fauna for each sub- area iin the Middle Atlantic Bight TEELOM 2. .. 2 .. .... 1 =e n o men ol e cl ol onal ne me ae me ne mal e ae i a on he he s 12 ana ne rear me he me ie ie me me ve N19 7-79. Maps of the Middle Atlantic Bight region showing the geographic distribution of: 7. Density of all taxonomic groups combined 24 8. Biomass of all taxonomic groups combined 25 0. Density SOT POTITATA !... .... .. . _. .. cw. . .. Ll) o ula ee nees anal a mn aie aem aler inin n ince anne inn alg tn anne e ee wie 26 10; iof PorifoPA . .. . .. . . .- cu.. o- coule on anl a olmak a n ann hem n alee ae mole arie a it ake ar aa a i ab ir ani a 'n i bee ae 27 11. DensitylofiCoelentarata . .. . _.. . ..... .. .. .. .. .. .. . _. . as 22 aol un nn sl ule onn Lee o me o u mao a me e a we ag oe oen te we tales cs 28 12. sof Coclenterath wasa 29 18 Densityiot Hydror0a aareskeers onl ass mn l 14. ~RBiomases Of '.. .. .. .. . .. .... .. o o LL. n. + cl ton mo le o ne in he be ae ue an hl m m n wh he ie PEH il a as a. an arie ie it le n an n hoes in mas i n a e se 31 15; Densitysof AlCyONATIA .... .. .. 2... 2 .. cs io oon nl o cl e bral a oe ne hn n hes e me ne he i haley in Hn ag ar r s ae ne alee in r ar ie hn te me aer nd a a ae 82 16. Blomass ... .. .. . .. c.. .. .. cll L2. .. 2 ll Lee el nae pu ilo len enne lanl none anu ann anne ae wee ies 33 1 foanthariq .. ._. ._ s neue nage n coe n e nes .o, ome eatin s auih 84 T8 S Blomass of iR ) ... .. .. 2. .. .. 1) .. . 2 o. ll cl cll os w helen bo nnn m ce e on ane o. on ue me nn in ao hi he male bn at ae We e u ie ie r He be e an oe eni a te ae 35 10. Density of .._... .. .. .. .. .. .. o. o on - oo n n tenn non oo o no oo on noel il ne me ae ot mune ae he adios te held ne G o oe he in n ues e e 37 50. Biomass of PlatyhelmInthes .... .... ... ..- .o on nso c oll carr anti eine a «ole 38 1: Density NOPANEeMmerbeq .... .. .. .. .. .. .. - 2. n. s o alle o sn nner n iene hein on meee nn l ih me ent Be n e oe a hn he ar it ur n ete ad inne e ae asin wee tf tn a 89 o. Blomasstof INEMeReR .... ..~ 2s. - ~s -c enas ans ss un mins iene aan mete calc 40 20. Density ip NematoGn .. ... ... ... . . .. . . .. _. .. n o . o nu nln cl o heel. onle aia i a eee ms m' ie min aP ee ie eee ines 41 As Biomass COL NeMALOUS | .. .. -- . - ... : . 2. - c. oo o 2) oo wel ne se wane te e ae ae an ee me me te maid cae n me al ann ne e an inne me in il m e ie he ve me ee 42 25. Density ROP ATMENAN .. .. .. .. C2. -. c _.. o o 2 ll a oll ol no el ah oe eol oo ne cl une on he oe ae ae ae on Be We Wn te nt mn e an an ae he aie maid ie e ee ie we ae area 48 2 Riomagsiiof AMNCILCE _.. .. .. .. .. .... .s .. .. .. _... .. - an whl ae ie be on me ie in ae od e ce e ae ue e on e me e oe e an a an me an e hn h Se on e n in te on e og he 44 S 6.. Density 'Of" ' ... .. .. .. . .s _ .. .. +2 oo n l En io hane Ge oe we he ae ae ae te an ae e anja ne e oe e nes ne ae n on fu in e Se fae an oe ne t ie 45 28. Biomase of, POGOMODROTE -. _. ... c. .. .. . c. .o no. ol o sen o nen b ne ne me hebe nh ann u oe i he hace ae ao ia ae ha oe ma ve ie in tn e aho me ce we g e 46 9. Density BOPARIDUNCUIA . .. .. .. . . .. :. .. . 32. .. . oul cl te oo coe i be me a ee me we le ae in me he ar eur ae ue me e e me m ue r ne e me ae in ae tbe n e tn e aaa se A7 $0.) Bromassiof .. ... ...... . .. _ .... .. .. c. os o. oo o a soo o ol a ee ae m hee he nne mn on me heat Hee n e e ae el at ae e oe on s l el m s or he e hi ie ald 48 $1. Density fof Echinra' and . - .. .. .. .s - on o o ol no he no he he an nn mn me e h ee al he a r ae he me ne rr mean moim ar He he ie an mee me 49 $92 Blomass of Echivura and 10.0 conn nnn non de nnn 50 S8" _ .... _ _ : .c acco ol cou cn cnl PL De oun enn ann an s 52 04. BiomassIOFIMOIIUSCA .... .. _ :. - -n ane c cee wo o wee cane enne anna 53 35. Density of Cephalopoda and Polyplacophora L_.__.__________L_____L__________LLLLLL__ 54 $6. Biomass of Cephalopoda and Polyplacophora 55 8%. Dengity 'of GaStFPODPOUA .. . .. ... - ce. ne len nacl n ann bo nne nl m e inane ceanan abe ani es 56 88. Blomass of GastrODOAAR |.. _ .. . . - .... _ .. cll cu nano neonl nln nnn nn ane mnie a ae in mac aa alias 57 29. Density of BivaIvisq . . ...... .. .. ... .. . c 2) s 22. ol l onn dion toe ol c ooo olo oo o a heve mae ie me man ae me in o er a in aie ie s ae oie ne 58 40; Biomassibf BIYVAIVIA .... _.. . .. ... .... .. .. llorar nn nnn eno none e rnm an am' mo inin niin aa an ne a mae 59 41. Density of SEADROPOUAR -... ... .. .. .. _. . .. 2 u oo nln ol ol nal un uue nnn een dn onne nn ien nen name ae aul 60 42. Blomass iof .... ..... l. 61 49. Density 0f ATERFOPOUA 220000... noe or nc ens in 62 Ad; .. ... .. .- . . .. o cl l a be in oe ne alel tl be nol hn he ue ur ne mre an oo e e ne ah u oo e e nf He oe an ne me t an an heeler ne s ac ar be ae wn on ines 63 45. Density of Arachnida, Copepoda, Nebaliacea, Ostracoda, and Pyenogonida _____________ 65 46. Density Of Cirripedia ns nits aem 66 47. Biomagssof ACITTIGEAIN ._ _...... .. . ... . _o Lona in en nnn n ann nn a aneanbeds anes nake s 67 48. Dengity "of CuUInACEA -.... .. .. _ _._. _ L __ tie an biens ans 68 19. ~Riomass Of JICUMACEALL _._. _. _=.-«.21- ._ antenne ss bis bec tb fins! 69 508 Density of! \.. .. .. .. . . .. .. 2. o. n 2 2 ss hon cine ao ue n a one n ae oo cl ae on ane ir wan e me me e ae msn mt ae hae i in te ae an ale a' a aeg 70 $1. Of .......... , ;-... .. cure alte be on aie sn ab sun fhi'n sant ant cand tr 71 52. Density Of ISODOUA |.. .. .. .. .. .. .. - - a u. a a m a oo ao ae os oe he moc mo nne Hem one os mae to Se t in in Aa t on Ne i n e ae he t be ore e in e in he ae tale ae e 72 58. BIOMASS IOL TSODOUSL (- c. .. ..... ... .. ». . :. =) 1 - « -, s t so nn os mn mcr oe on e oo mn m Heine oe ae on So hn t e I2 r t et he he ae ne e at hes ae ut e In me me me's, or nme ie 78 94.. Density BOF AMDRIDOUS -. .. .. .. .. .. .. 2 -. .. 2 c) cul acl 1. nne nl 1, ne cl ce ae ae 52 he ce w ee i He nded In ine ae m ian e hue n ane bn e bi e o te pee in in he 74 65. . Biomass Of AMDRIDOUA "-.. .. ..... ..... .... ..... ... _. .nu ..o ol aul ll ll o oin lll nl ll ele ce n oen ll aon nnn nne ene nes 75 £66.) Density ROF MYyEIAACEAR ... .. . .... .. .. .... .., . .. c. c. nnn nn neonl lon nnn nn dann nene an ae ain reais ine ma eels 76 57. Biomass lof MySIGACER ... ._.. . ._.... ...l... Cork 58. Density of DecBDOUAQ ......-.... ~.. ..on >=» bann ssansnews tn wets ss care 78 59... Biomass of DeCADOU®! -..... .. .. ..... .. 3 « >. -. - n - .+ - t hone miele nnn he n ao in be ie in name h an in in al ae e alan als hae ie arn n ao Ee p an a a a 79 60. Density of Bryozoa and BraCHIODOGUA .. . .. .. . _. .. _ _. .. cnl nl oll ll ul non nn len nn ann nona nn anna an 81 61. Biomass of Bryozoa and Brachiopod® 82 FIGURES CONTENTS 7-79. - Maps of the Middle Atlantic Bight region showing the geographic distribution of-Continued 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 78. 74. 75. 76. 77. 78. 79. Density - of Echinodermata Biomass of. Eehinodermats Density of Holothuroldeq Biomass of Holothuroitdea .................. Density. .of EehInGfGeS . ..... . _...... ...l ul, l sols ou un aise n me n m an me he m rer he m an in ean n e moe ae ae te oe he se are in m he Biomass. of :.. .. .. .. C_ .o. cl o Gh olo co an ae me ml m ne me ne oon a oe ue 'ma he as mae he ae me me os on we me oe e me i nn a Se he on oe fu he i ie 4s Density..of Ophluroldea atms Biomass of OpHILNLPOLOOR ... 2 ill l. 2 ol 2 an noo anl cl boe oo aln she he an me a me bo oe me e ma eh oe e he e oe an i se im ms at oe me ie oe me me ie ne se oe Density of ... ..... _. .. ... ...l l ollo ull he uu h an n h me ne Sh me me he m te se we oni m on on he m sno ie te m ie te ae me me oe ie ne ne males Biomass of ASterOIGeB Density of Ascidiacea and Hemichordata __________________________ccccccccccc______ Biomass of Ascidiacea and Hemichordata _____________________________cccccccc______ Three selected species of Annelida and one Pogonophora ____________________________ Selected bivalves, phylum MollUSca Selected bivalves and gastropods, phylum Mollusca _________________________________ Selected amphipods, phylum Arthropoda A selected isopod and decapods, phylum Arthropoda ________________________________ Selected echinoids, asteroids, and ophiuroids, phylum Echinodermata __________________ 80. Graph showing relationship between number of individuals and water depth for each subarea and for the entire Middle Atlantic Bight region 81. Graph showing relationship between biomass (wet weight) and water depth for each subarea and for the entire Middle Atlantic Bight region 82-87. Graphs showing density and biomass in relation to water depth in the entire Middle Atlantic Bight region for: 82. 83. 84. 85. 86. 87. Porifera, Hydrozoa, Alcyonaria, Zoantharia, Platyhelminthes, and Nemertea __________ Nematoda, Annelida, Pogonophora, Sipuncula, Echiura, and Priapulida _______________ Polyplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda, and Pyenogonida _____ Ostracoda, Cirripedia, Copepoda, Nebaliacea, Cumacea, and Tanaidacea _______________ Isopoda, Amphipoda, Mysidacea, Decapoda, Bryozoa, and Brachiopoda _________________ Holothuroidea, Echinoidea, Ophiuroidea, Asteroidea, Hemichordata, and Ascidiacea ___. 88. Map showing geographic distribution of bottom-sediment types in the Middle Atlantic Bight region 89-94. Photographs showing: 89. 90. 91. 92. 98. 94. Gravel bottom at a depth of 23 m in the Nantucket Shoals region, south of Cape Cod, MASS | .. .. 2 sl 2 ol s 2 ann B nelle ce be me m ie ne He me w an Wl ns ae m me en oo be Suse ehe oe me os on hn s oe e to e ae un mein un ae oe se im ae oe ma Sn soe oe se ke ae Sand bottom, containing small amounts of shell, on the Continental Shelf northeast of Cape Charles, Va., at a depth of 48 M . Silty-sand bottom at a depth of 406 m on the Continental Slope east of New Jersey _____ Sand bottom inhabited by a dense assemblage of sand dollars (Echinarachnius parma) at a depth of 48 m near midshelf east of Delaware __________________z___________ Sand-shell bottom at a depth of 69 m near the Outer Continental Shelf northeast of Cape MBY; AN. I. | ... -. 1 l o a oon ce te s ne an he eme ue se sein ol hn me A on on i onne t n ue oe me mt nene on n Ae e e m me an t ie m ie me i m me Al an at e onle ae Silty-sand bottom at a depth of 178 m on the Outer Continental Shelf near Hudson Chan- nel, south of New York City COLL OL 95-104. Graphs showing: 95. 96. Relation between number of individuals and bottom-sediment types for the entire Mid- dle Atlantic Bight FeRION ... ... .. . _ . _. . . .o. nl lo oe ooo noe nene oe ee emi m ua one Relation between biomass and bottom-sediment types for the entire Middle Atlantic Big NG - PERLOT £.. .. . .. a 2) c. an ol neice l cn ue ne colle ue wl e ar on e t o me e e m ae ut e un im ms ae an n me ame sae se me s se ae se ot an n n ae an ue ar od mn ne . Relation between number of individuals and bottom-sediment types for each subarea __. Relation between biomass and bottom-sediment types for each subarea _______________ Density and biomass in relation to bottom sediments in the entire Middle Atlantic Bight region for Porifera, Hydrozoa, Alcyonaria, Zoantharia, Platyhelminthes, and Nemertea 104 110 111 112 113 114 115 125 126 127 128 129 130 131 133 134 135 136 VI FIGURES CONTENTS 95-104. Graphs showing-Continued 105. 106. 107. 108-118. 114. 115. 116. 117-122. 123. 124. 100. Density and biomass in relation to bottom sediments in the entire Middle Atlantic Bight region for Nematoda, Annelida, Pogonophora, Sipuncula, Echiura, and ! 2 2 SEL Le Ll l cl ann 2 cl tee o i te he ae nece ca oe in a oo ae oe elie he in hu he m n oe moe be e Be he we at e te as on ae t at Be im an ad he n in Ge we 101. Density and biomass in relation to bottom sediments in the entire Middle Atlantic Bight region for Polyplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda, a" 3 300.1. 2nd ee a ed e U o a ie rane ae ie melee in he ae ie a as ae B et r e me an Bn He se be n oe s e ae or i n Se be bn nn on an ie ie e i e 102. Density and biomass in relation to bottom sediments in the entire Middle Atlantic Bight region for Ostracoda, Cirripedia, Copepoda, Nebaliacea, Cumacea, and Tanaidacea . 103. Density and biomass in relation to bottom sediments in the entire Middle Atlantic Bight region for Isopoda, Amphipoda, Mysidacea, Decapoda, Bryozoa, and Brachiopoda __ 104. Density and biomass in relation to bottom sediments in the entire Middle Atlantic Bight region for Holothuroidea, Echinoidea, Ophiuroidea, Asteroidea, Hemichordata, and ASCIOIALEA " 222 L o co o sone o a aa ae e cd H at hn we ie ue an save eae on he oe e alas or hn as oe us it e m uted on me we a us tn sue asi ua e un Ne e os re re inne oe Map showing the geographic distribution of organic carbon in the bottom sediments of the Middle region t_... .. 2. .. .. .. _L. 2 .. 2. l 2 u. 22 uo. cece m a ed ae me me an e an he he es oe ue a on oe Ml e Ne o s a e oe l as e n inl an in e m oa olen os Graph showing the relation between number of individuals and sediment organic carbon for each subarea and for the entire Middle Atlantic Bight region ________________________________ Graph showing the relation between biomass and sediment organic carbon for each subarea and for the entire Middle Atlantic Bight regi0n Graphs showing density and biomass in relation to sediment organic carbon in the entire Middle Atlantic Bight region for: 108. Porifera, Hydrozoa, Alcyonaria, Zoantharia, Platyhelminthes, and Nemertea __________ 109. Nematoda, Annelida, Pogonophora, Sipuncula, Echiura, and Priapulida _____________-- 110. Polyplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda, and Pycenogonida _____ 111. Ostracoda, Cirripedia, Copepoda, Nebaliacea, Cumacea, and Tanaidacea ____________-- 112. Isopoda, Amphipoda, Mysidacea, Decapoda, Bryozoa, and Brachiopoda _____________- 113. Holothuroidea, Echinoidea, Ophiuroidea, Asteroida, Hemichordata, and Ascidiacea _____ Map showing distribution of the range in bottom-water temperature for the Middle Atlantic Bight TEFLON £.. ae aun ain ale c ce ie us wea oe me an a ae as mla cal a r e te hr n mnt ae or e u Be ue As a e A s 1 s me an enn r ed e HW e oo Ie Ti ms in An in on ae oe ae A e Ch oe un ae rhe e Graph showing relation between number of individuals and range in bottom-water temperature for each subarea and for the entire Middle Atlantic Bight region _______________________- Graph showing relation between biomass and range in bottom-water temperature for each sub- nrea and for the entire Middle Atlantic Bight regiOn Graphs showing density and biomass in relation to range in bottom-water temperature in the en- tire Middle Atlantic Bight region for: 117. Porifera, Hydrozoa, Alcyonaria, Zoantharia, Platyhelminthes, and Nemertea ________- 118. Nematoda, Annelida, Pogonophora, Sipuncula, Echiura, and Priapulida ____________-- 119. Polyplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda, and Pyenogonida ___ 120. Ostracoda, Cirripedia, Copepoda, Nebaliacea, Cumacea, and Tanaidacea _____________-- 121. Isopoda, Amphipoda, Mysidacea, Decapoda, Bryozoa, and Brachiopoda ______________- 122. Holothuroidea, Echinoidea, Ophiuroidea, Asteroidea, Hemichordata, and Ascidiacea ___ Map showing the geographic distribution of the number of individuals for each dominant taxon in the entire Middle Atlantic Bight regl0n sme Map showing the geographic distribution of the biomass for each dominant taxon in the entire Middle Atlantic BIGhE PeSION . .. .. .. .. .. .. .. _ . .. 2. cll, 2. c.... oo hane le bn coli mle ame mee we a se we amos me me one te e he h ue oe tn te os hn as te We he in is Page N140 141 143 144 145 152 1583 159 160 161 162 163 164 165 167 168 169 173 174 175 176 17% 178 193 194 TABLE 1. o yo 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 28. 24. 25. 26. CONTENTS TABLES Research vessels, cruise identification and dates, and number of stations sampled ______________________ Areas of several bathymetric zones within each subarea and total area of Middle Atlantic Bight region __ Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individ- uals and biomass, representing the entire Middle Atlantic Bight region ____________________________ Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region __ Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individ- uals and biomass, representing the Southern New England subarea _________________________________ Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individ- uals and biomass, representing the New York Bight subarea Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individ- uals and biomass, representing the Chesapeake Bight subarea ______________________________cc______ Number of samples within each depth range class in each subarea and for Middle Atlantic Bight region __ Mean number of individuals and biomass of the macrobenthic invertebrate fauna in relation to water depth for each subarea and for the entire Middle Atlantic Bight region __________________________- Change and rate of change in density of invertebrates in relation to water depth _____________________ Change and rate of change in biomass of invertebrates in relation to water depth _____________________ Mean number of individuals listed by major taxonomic groups for each bathymetric class, representing the entire Middle Atlantic Bight | PE&ROTM . -.. . . _... .. .. .. . sul .s cL ollec ol olo s eee e e hn oe e e m me mone he meme me me t meme me meme oe me e al in mine wh aia ss Mean biomass listed by major taxonomic groups for each bathymetric class, representing the entire Middle Atlantic ; - .. .. .. .. s o n cl clo o olo nne o ieee tie m ie ma ce me e oe oe wee ho we e us be oe m he tlt s nie e y m ae ue Bn hm p we me are ue He e e ae e S2 ue un tn l se ie Mean number of individuals listed by major taxonomic groups for each bathymetric class, representing the Southern New England SUbDATER: .. . 2 au ol ol ol oo al oen o. ol oo no nene oe hee as nobel i on be p hn oo me me Be w mou on for hu s m me oe ae me ft e m s ws s e oe tn io me un Mean biomass listed by major taxonomic groups for each bathymetric class, representing the Southern New England SUBATOR | L . o . suo a heel on o oo a eh nle i Heeled ie he in on me hohe me me me an me mes un se oa me i me am uo e me me hs os an ie m me s s e e e se ae h on ae e Se lo se he a he me Mean number of individuals listed by major taxonomic groups for each bathymetric class, representing the New York Bight subarea .. _.... . . .... .. .. .. .. .. u. n lll can as ool oo do ool he he me bene ee me he me we he ie he he ar n me ae un e te ne er on an he e he te he mead ie me in id be Mean biomass listed by major taxonomic groups for each bathymetric class, representing the New York BIght _ .. . LL . 2. l 2 o lll s onl o hle o on ooo peee PMH c e th lan e ce We un an oe ue an ms us hee an an lt me me e a oe me e me me he m us ue we h ne ne hon un i e he ave te he on he Sh ie i Mean number of individuals listed by major taxonomic groups for each bathymetric class, representing the Chesapealto BISHC . . . .. .. .. .. .. . co o cohen ll clo nul oo oo ml hein whe no tn m mae mn me oe an h on e as me an n e oe he m oe me u on m us e n n e hn e iron bn ue ne ae e se e in Mean biomass listed by major taxonomic groups for each bathymetric class, representing the Chesapeake BIGht SUDATER 2 .. a cll. coo as oohh ol tol ol cl . ol ecs ol e w me b nn bo os n me ae e ooo ue ue e os e ho oe us e o us im me h e Ir ut os to me nice te ir e Se he ue on Seh im oe on halos ne Be e ie oe me hn an e Tale Number of samples for each bottom sediment type in each subarea and for the entire Middle Atlantic BIShHC TERION . .. c. . .. ..... .. o. ul Wol cle s oo h he so me be Tonle a Gs i s s l e e a rien a hr ae ie lor oe se me e be ue us e We et on e mn nt me 'u wn ne oe us wa 'un ae an sa nt on at a n ne s uu ie on ts e te Re Mean number of individuals and biomass of the macrobenthic invertebrate fauna in relation to bottom sediments for each subarea and for the entire Middle Atlantic Bight region ________________________- Mean number of individuals listed by taxonomic groups in each bottom-sediment type for the entire Mid- dle Atlafitic BIGHE Te@LOH . - 2 . .. .. - L. m ne a. as se Hee wa o oo nee be ue an ae m is n as e he e in e W he me e t, an s me un me ue un on an ue an tt e me im e e e n i a P ad an te me he he w fe ha Mean biomass of each taxonomic group listed by bottom-sediment type for the entire Middle Atlantic Bight . .. a 2. . ns c ud cs ae seee nce aa ce ae te ue melon t e e us he at H l ue ane Bn hn hs ae ne l nn Sn in oun os an me m me ue nne us oe me te u nn i tu es ms se me as oe on ek an ae nt nn i hn W e ue ue in ae ae in he vee Mean number of individuals listed by taxonomic group in each bottom-sediment type for the Southern New England ... .. . .. .. .. o .. .. l ll .l nnn o olo ol cul cl cl o cn tiie a a ue cee se ee we e m te oe e h Ton he e r sos a i e y mus me me's he hn te se he ue to te me erat e mabe hs eke ase Mean biomass of each taxonomic group listed by bottom-sediment type for the Southern New England .- c 2 col 2s oo ns oe oh cl e no ol io ol boe oe he me clas me we a e B4 ot w m e anld io u mn me t ose fed us e i e is on on 50 us un an ue u s nuo an anon i ma s 'e in noe us me m ine se oe He un ue oe mt s sm ue he eal ieee Mean number of individuals listed by taxonomic group in each bottom-sediment type for the New York SUDATEOR ...... .. L.. o o o. .. o. ae n s cl no al wn in be me be an hn an m rae a ut an ae ue te tn un eh oi in a 94 ue ur o up eo as tn ue sn asus to Me i m 'on oe mo hr or ue fr we ee Bo Be e an ae te ie oe on h l te he n Mean biomass of each taxonomic group listed by bottom-sediment type for the New York Bight subarea Mean number of individuals listed by taxonomic group in each bottom-sediment type for the Chesapeake BIghE SUDRTER: ... . .. L ..... .. . _. . ul loll ool sel tn n n he ml ae al we he cn s e we e a oe u ur us is e ir os ae r anus ue on as 55 oe ue un an me m ts ue ue i ne be s u s b un us om e i ne on to aioe oe in ip oe he Mean biomass of each taxonomic group listed by bottom-sediment type in the Chesapeake Bight subarea __ Number of samples for each class of sediment organic carbon in each subarea and for the entire Middle Atlantlit BIght region .. .. .... .. .. _. .. J .. .o ul ol nll ol nl cele ce e mm mme moe ae mete tre Se mon ues a or ue me ue oe ue e bo e im ue 5 me Se uss n he e oe me mus he we A arie e on to he ap e oo oo VII Page N5 5 11 13 20 21 22 101 101 105 105 108 109 116 117 118 119 121 122 124 132 138 139 146 147 148 149 150 151 154 VIII TABLE 31. 82. 33. 34. 85. 36. 87. 38. 89. 40. 41. 42. 48. 44. 45. CONTENTS Page Mean number of individuals and biomass of the macrobenthic invertebrate fauna in relation to percent organic carbon in bottom sediments for each subarea and for the entire Middle Atlantic Bight region __ N154 Mean number of individuals of each taxonomic group listed by sediment organic carbon content class, representing the entire Middle Atlantic Bight Peglon ._.. .... _._. .. . _ _... . 2 cull no lull on o cl cl oooh he an nn bn me m ue e me hse ae e me te me 155 Mean biomass of each taxonomic group listed by sediment organic carbon content class, representing the entire Middle Atlantic BISHC FOR LON | - .. _ _. .. .. .. _. _. .... . L) .. .. .. - - be c. an on he ha he ee t u aon an maa ns e am at s me a m me me ne he s he he e t e as ne h o i b line 156 Mean number of individuals of each taxonomic group listed by sediment organic carbon content class, rep- resenting the Southern New England subarea 157 Mean biomass of each taxonomic group listed by sediment organic carbon content class, representing the Southern New England RubDaPFon! .s _. 2. cll 2 c hll ee ll ll Ll ll ooo os cl Hl he me ice be a an c Geon oe ine m ae an oo one m o m f os oo on oe Safed m h te mid ne an he in 158 Number of samples within each water temperature range class in each subarea and for the Middle Atlantic Bight TesLOn . co l l .. L L2 Ld L. .. o ce ocal nse ol oe 1 tali ay aler t h h meng n am an Be t me te au in elan a manet e me e an f hue Ne t o B 40 m h 1 oe hn i i i 166 Mean number of individuals and biomass of the macrobenthic invertebrate fauna, all taxonomic groups combined, in relation to range in bottom-water temperature 166 Mean number of individuals of each taxonomic group listed by temperature-range class, representing the entire Middle Atlantic Bight region _ -_ _ _ . _ .. __.. c_. _ . 2.2 en ee reel ELL L onn sn om bba he me a oe whe me hie in oe t oe me ane o a m 171 Mean biomass of each taxonomic group listed by temperature-range class, representing the entire Middle Atlantic Bight regLon 12.22.0220 cull lll. l ol o eee nul om o he on he e te me h hme aus ae me he oa ados on fl r t l ame me me ne e fre t me mean se sh s he bs 172 Mean number of individuals of each taxonomic group listed by temperature-range class, representing the Southern New England SUDATER \.. _ L. 1 c ol cle ol l lll ll L n eee e al mn un me ms me hrn u t oras ne woot as as h ms e l el he m e e a ae e ae u oe h a ie 180 Mean number of individuals of each taxonomic group listed by temperature-range class, representing the New York Bight Subares .. . oo cul Ll oun Ll ull cn o oe e on oe eee heh mn me tehe n nn mine To ne Sh me Be he m oe dn me ein ie fre oe he ie oe he ie a is 181 Mean number of individuals of each taxonomic group listed by temperature-range class, representing the Chesapeake Bight subarea 182 Mean biomass of each taxonomic group listed by temperature-range class, representing the Southern New England subarea LL.... ecg ll lll l l ll ol dol Sei a od anne ae t os ee an onn p e oe he he ond Ge is m he me ne mn on ue ase ue hn he m he tee ae me an ae he ve 183 Mean biomass of each taxonomic group listed by temperature-range class, representing the New York BIGEhHE SUDATER \.. .- 2 2 2 o on AL t te s ae as a ee he ae ae ae a t a te ae ne e ae oe me an me g t s a r S me m op m ms me me n oe or oe ye ce od t o me to he oe mn me e nd l ie ane r he e me ue os hear in a t 184 Mean biomass of each taxonomic group listed by temperature-range class, representing the Chesapeake Bight SubRFER soul nes so ag do no o cle coll L ll l cl oce n eae He we oe mn ie moe a ar he aas te he os ahl n me an Sn he s me ae o Me e n hn han ' on en an se he wea mn e 185 4 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES-- MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION-FAUNAL COMPOSITION AND QUANTITATIVE DISTRIBUTION By Roranp L. Wicury * and Rocerxr B. THErRouUx ' ABSTRACT In the early 1960's, a quantitative survey of the macro- benthic invertebrate fauna was conducted in the Middle Atlantic Bight region. Purposes of this survey were to obtain a preliminary measure of the macrobenthic standing crop, particularly of biomass, and secondarily, to determine the principal taxonomic components of the fauna and the general features of their distribution. Sampling was con- ducted at 563 locations; water depths ranged from 4 to 3,080 m. An analysis of faunal composition and of quanti- tative distributions from the survey is presented in this report. Quantities are expressed in terms of density and biomass. Dominant taxonomic components in numbers of individuals were (in percentage of total fauna): Arthropoda (46), Mollusca (25), Annelida (21), Echinodermata (4), and Coelenterata (1). Dominant in biomass were (in percentage of total fauna): Mollusca (71), Echinodermata (12), Anne- lida (7), Arthropoda (5), and Ascidiacea (2). The quantity of fauna, both density and biomass, decreased substantially from shallow to deep water. Another major trend was the marked decrease in quantity from north to south within the Middle Atlantic Bight. Bottom sediment composition strongly influenced both the kind and the quantity of macrobenthic animals. Coarse-grained sediments generally supported the largest quantities of animals, including many sessile forms. Fine-grained sediments usually contained a depauperate fauna; attached organisms were uncommon. No obvious cor- relations were detected between the amount of organic carbon in bottom sediments and the quantity of benthic animals present. Marked seasonal changes in bottom water tempera- ture were associated with an abundant fauna composed of diverse forms, whereas uniform temperatures throughout the year were associated with a sparse fauna composed of a moderate variety of species. Taxonomic groups that were dominant in a significant number of samples, in terms of number of individuals, were: Bivalvia, Annelida, Echinoidea, Ophiuroidea, Crustacea, and the bathyal assemblage. Groups dominant in terms of biomass were: Bivalvia, Annelida, Echinoidea, Ophiuroidea, Holothuroidea, and the bathyal assemblage. * National Marine Fisheries Service, Woods Hole, Mass. 02543. INTRODUCTION This report * describes, in quantitative terms, the macrobenthic invertebrate fauna inhabiting the Middle Atlantic Bight region. It deals primarily with faunal (a) taxonomic composition; (b) geographic distribution; and (c) relationships to bathymetric level, bottom sediment composition, sediment or- ganic carbon, and water temperature. Regional dif- ferences in faunal composition and quantitative dis- tribution within the Middle Atlantic Bight region are analyzed and documented.} Further studies of these data, in addition to the primarily descriptive analyses presented here, are in progress. RECONNAISSANCE SURVEY A reconnaissance survey of macrobenthic in- vertebrates in the Middle Atlantic Bight region .was conducted as part of a larger survey of the entire Atlantic coast of the United States (Emery and Schlee, 1963). This survey by the Bureau of Com- mercial Fisheries (now the National Marine Fish- eries Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce) was conducted in cooperation with the Woods Hole Ocean- ographic Institution, Woods Hole, Mass., and the U.S. Geological Survey. The major objective of the biological phase of this survey was to obtain an overview of the general composition and distribution of the macrobenthos. Sufficient understanding of the * Financial support for the preparation of this report was provided by the National Oceanic and Atmospheric Administration (NOAA), Marine Ecosystems Analysis Prigram, New York Bight Project, Stony Brook, N. Y. 3 An earlier, unpublished report, '"Macrobenthic Invertebrate Fauna of the Middle Atlantic Bight Region: Part 1. Collection Data and Environ- mental Measurements," by Roland L. Wigley, Roger B. Theroux, and Harriett E. Murray (1976, 34 p.), is available at the Northeast Fisheries Center, Woods Hole, Mass. N1 N2 fauna, especially the distributional aspects, was de- sired to permit the rational selection of one or more communities of benthic animals for detailed study. One or two of the more important communities or associations, suitable from both the practical and the theoretical viewpoints, will be selected for de- tailed study of taxonomic composition, productivity, interspecific competition for food, and related as- pects. This latter phase of the investigation is in- cluded in the long-range objectives of the National Marine Fisheries Service for studying food-chain dynamics as they pertain to fish production on the Continental Shelf off the Eastern United States. Because of the need for measures of energy flow in the production cycles, emphasis in the benthic sur- vey was placed on measurements of biomass (re- ferred to as wet weight or damp weight), and num- ber of individual animals per unit area (density) was considered secondary. MIDDLE ATLANTIC BIGHT REGION The Middle Atlantic Bight region is defined as that body of water overlying the Continental Shelf off the Northeastern United States, bounded on the north by Cape Cod and Nantucket Shoals, Mass., and extending southward to Cape Hatteras, N. C. Its shoreward boundary is the coastline; its seaward boundary is the upper margin of the Continental Slope, the so-called shelf-break or outer edge of the Continental Shelf. The geographic region included in this study consists of the Middle Atlantic Bight proper, plus the adjacent inshore bays and sounds, and the offshore extension that consists of the Con- tinental Slope and the shallower part of the Conti- nental Rise (fig. 1). This larger area is called the Middle Atlantic Bight region. For purposes of com- parative description, this region has been divided into three roughly equal geographic subareas: Southern New England, New York Bight, and Chesapeake Bight. PREVIOUS STUDIES Although no previous quantitative studies of the macrobenthic fauna encompassed the entire Middle Atlantic region, comprehensive studies of small see- tions of this region, a few rather large-scale qualita- tive studies, and numerous reports of an ancillary nature have been made. Altogether, substantial lit- erature exists on this general subject that has been produced at an ever-increasing rate since about the middle of the 19th century. A few examples of the early reports are those by: Adams (1839), on new species of mollusks; Agassiz and Agassiz (1865), on ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES echinoderm morphology and development; Desor (1848), on the natural history of benthic inverte- brates from Nantucket Shoals; Leidy (1855), on the invertebrates from coastal waters of Rhode Island and New Jersey; and Verrill (1866), on new species and ecological observations on New England coelenterates and echinoderms. Early studies pro- vide some of the basic taxonomic framework for this fauna, provide clues to the pattern of geo- graphic distribution, and give a preliminary insight to regional ecology. Two classic reports in the early literature that deal with major surveys of inverte- brate animals within the Middle Atlantic Bight region are: (1) the U.S. Fish Commission survey of Vineyard Sound and adjacent waters, conducted in 1871-73 (Verrill, 1873) and (2) the U.S. Bureau of Fisheries survey of the waters of Woods Hole and vicinity, conducted in 1903-05 (Summer, Osburn, and Cole, 1913). Both surveys dealt mainly with epibenthic invertebrates and covered much the same area-primarily Vineyard Sound and Buzzards Bay in southeastern Massachusetts. Six published indexes and bibliographies provide good coverage of the general literature pertaining to the benthic invertebrates (and related subjects) of this region. The citations in these bibliographies include many old and new reports. The six reference works are: (1) "Publications of the United States Bureau of Fisheries 1871-1940" (Aller, 1958). (2) "A Preliminary Bibliography with KWICK Index on the Ecology of Estuaries and Coastal Areas of the Eastern United States" (Living- stone, 1965). (3) "Marine and Estuarine Environments, Orga- nisms and Geology of the Cape Cod Region, an Indexed Bibliography, 1665-1965" (Yentsch, Carriker, Parker, and Zullo, 1966). (4) "The Effects of Waste Disposal in the New York Bight" (sections 8 and 9) (U.S. National Marine Fisheries Service, Middle Atlantic Coastal Fisheries Center, 1972). (5) "Coastal and Offshore Environmental Inven- tory, Cape Hatteras to Nantucket Shoals" (Saila, 1978). (6) "Bibliography of the New York Bight: Part 1 -List of Citations; Part 2-Indexes" (U.S. Na- tional Oceanic and Atmospheric Administration, 1974). A sizable part of this benthic invertebrate litera- ture deals with topics having little relevance to the present quantitative study. Reports consisting of species descriptions, many of the studies of physio- MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N3 /SOUTHERN NEW EgGLAND € s } 436, x __ rige is CHESAPEAKE ) of/ 11>? FigurE 1.1-Chart of the Middle Atlantic Bight region showing the location of geographi- cal features and the three subarea divisions: Southern New England, New York Bight, and Chesapeake Bight. N4 logical processes, morphology, habits and behavior, parasites, diseases, growth rates, and similar topics are peripheral to the central theme of quantitative distribution. Another large segment of the literature (also only marginally pertinent to the present study) pertains to pelagic larval stages of benthic inverte- brates, intertidal fauna, some aspects of fishery re- sources, predation, commensalism, and other related subjects. Quantitative studies of the benthos have been con- ducted at various locations throughout the region in more recent years, particularly within the last two decades. Most of these studies were made on inshore and coastal regions, few on the Continental Shelf, and fewer still on the Continental Slope and Rise. The principal quantitative reports that we consulted in evaluating distribution and relative densities and (or) biomass are listed separately (although there is some overlap) for the following three zones: (1) inshore and coastal waters; (2) Continental Shelf; and (3) Continental Slope and Rise. (1) Inshore and coastal waters.-Southern Massa- chusetts, Rhode Island, and Connecticut: Lee (1944), Sanders (1956, 1958, 1960), Stickney and Stringer (1957), Phelps (1964), Rhoads (1963), and Parker (1974); New York-New Jersey: Dean and Haskin (1964), Franz and Hendler (1971), Phillips (1972), O'Connor (1972), D'Agostino and Colgate (1973), Kaplan, Welker, and Kraus (1974), McGrath (1974), and Dean (1975); Delaware to Cape Hatteras, North Carolina: Stone (1963), Tenore (1972), Boesch (1972, 1973), Leathem and others (1973), Palmer and Lear (1973), Maurer and others (1974), Watling and others (1974), and Watling and Maurer (1975). (2) Continental Shelf.-Wigley and MeclIntyre (1964), Emery, Merrill, and Trumbull (1965), Emery and Uchupi (1972), Pearce (1972), Rowe (1973), and Steimle and Stone (1973). An up-to- date review of the major species and faunal asso- ciations inhabiting the Middle Atlantic Bight was prepared by Pratt (1973). (3) Continental Slope and Continental Rise.- Sanders, Hessler, and Hampson (1965), Wigley and Emery (1967), Rowe and Menzies (1969), Rowe and Menzel (1971), Emery and Uchupi (1972), George and Menzies (1973), Menzies, George, and Rowe (1973), and Haedrich, Rowe, and Polloni (1975). Several ecologically oriented reports based en- tirely, or in part, on the samples used in this study have been published. Macrobenthos from a series of stations across the Continental Shelf south of ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES Martha's Vineyard, Mass., was included in a report by Wigley and McIntyre (1964). A description of sea-bottom photographs and grab-sample contents taken concurrently by the Campbell sampler (Emery and Merrill, 1964) was based partly on samples col- lected for the present study. An investigation en- compassing a large offshore area, extending from Nova Scotia, Canada, southward to New Jersey, that dealt mainly with the quantity of macrobenthic in- vertebrates in relation to bottom sediment types was published by Emery, Merrill, and Trumbull (1965). The quantity of benthic invertebrates in grab sam- ples from the Continental Slope off the Middle At- lantic region was compared with quantities observed in associated sea-bottom photographs (Wigley and Emery, 1967). A report by Wigley and Stinton (1973) on the remains of dead marine animals, par- ticularly mollusks, in a part of the Middle Atlantic Bight off Southern New England, was also based on samples collected for the present study. Several quantitative studies of the macrobenthos are in progress. Many of these studies are being conducted in coastal areas, and most of the studies pertain directly to assessments of environmental quality. In addition, two large-scale offshore investi- gations are underway. One is in the Chesapeake- New Jersey region in anticipation of petroleum ex- ploration, and possible production, in this region, and another is in the New York-New Jersey area. Impetus for this work is directly related to ocean dumping and waste disposal from the New York- New Jersey metropolitan area. A large volume of up-to-date benthic fauna in- formation is currently being issued in the so-called gray literature in which the results of recently com- pleted field studies are issued as contract completion reports, environmental impact statements, public agency (or private corporation) investigation re- ports, annual reports, or other similar special docu- ments. Many of these reports are issued in Xero- graphic or mimeographic form, often in irregular series or as a one-of-a-kind report, and, as a conse- quence, they often are not listed in the usual litera- ture sources. Hydrography of the Middle Atlantic Bight region is rather well known, at least the general features of circulation, tides, the annual cycle of temperature, patterns of salinity distribution, and other major aspects. Also, some inshore waters, such as Long Island Sound, Raritan Bay, and Chesapeake Bay, have been studied in some detail. However, detailed information concerning chemical properties, water currents, meteorological influences, and related as- MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION pects, particularly as they pertain to offshore bottom waters, is lacking. A bibliography of early (prior to 1951) hydro- graphic studies is included in the report by Ayers (1951). Rather broad consideration of the hydro- graphy of the entire Bight is given by Bigelow (1933), Emery and Uchupi (1972), and Bumpus, Lynde, and Shaw (1973). Information on water temperature was reported by Walford and Wicklund (1968), Colton and Stoddard (1972, 1973), Churgin and Halminski (1974), and others. Salinity and its bathymetric and geographic distribution are in- cluded in the reports by Bigelow and Sears (1935) and Churgin and Halminski (1974). Water circula- tion and related aspects have been reported by Chase (1959), Ketchum and Corwin (1964), Bumpus (1965), and Bumpus and Lauzier (1965). Geological information about the Middle Atlantic Bight region is copious and up-to-date. A few major references on this subject are: Emery (1966, 1968), Hiilsemann (1967), Ross (1970), Schlee and Pratt (1970), Emery and Uchupi (1972), Trumbull (1972), Hollister (1973), Milliman (1973), Schlee (1973), Swift, Duane, and McKinney (1973), and Stubblefield, Dicken, and Swift (1974). MATERIALS AND METHODS MACROFAUNA SAMPLES This report is based on the analyses of 667 quan- titative samples of benthic invertebrates collected at 563 locations (stations) primarily between 1962 and 1965. Three samples collected in 1957 were in- advertently included in the analysis of this suite. The basic sampling strategy was to plot an 18 -km (10-mi) grid whose base orientation was roughly perpendicular to the depth gradient. Station loca- tions for all samples are shown in figure 2. Basic station data is given in an unpublished report by Wigley, Theroux, and Murray (see footnote 1 in "Introduction"). The even distribution of stations imparted by the grid is evident, but is masked in some places by additional samples between grid lines. Samples were obtained during 16 research cruises (table 1). Five research vessels were used, three of which, Albatross III, Delaware I, and Albatross IV, were operated by the National Marine Fisheries Service of the National Oceanic and Atmospheric Administration in the Department of Commerce and its predecessor agency, the Bureau of Commercial N5 TABLE 1.-Research vessels, cruise identification and dates, and number of stations sampled Number of Vessel and cruise stations Cruise date ALB III-101 _____. Aug 21-80, 1957 3 DEL-62-7 _________ Jun 13-20, 1962 63 Gos-10 Apr 26, 1963 6 GOS-11 ___________ Apr 30, 1963 3 GOS-12 ___________ May 2-7, 1963 4 GOoS-18 .______.___. May 9-14, 1963 25 GOs-20 ___________ Jul 16, 1963 1 Go§-22 ___________ Aug 5-17, 1963 10 GOos-28 ___________ Oct 3-6, 1963 9 Gos-29 ___________ Oct 8-27, 1963 130 cogs °. ________ May 15-Jun 30, 1964 53 GOS-40 L Aug 1-29, 1964 129 AST-64-1 _________ Apr 22-23, 1964 6 AST-64-2 .________ Jul 1-Aug 9, 1964 74 ABT-O5-1 __.______ May 4-Jun 12, 1965 38 ALB IV-65-11 _____ Aug 17-27, 1965 14 > .. 1 res o s nee ae eee Pine in on iin arie a ione 563 Fisheries, then in the Department of the Interior. Two vessels, Gosnold and Asterias, were operated by the Woods Hole Oceanographic Institution, Woods Hole, Mass. Quantitative samples were obtained from inshore estuarine areas, the Continental Shelf, Slope, and certain parts of the Continental Riss throughout the Middle Atlantic Bight region, encompassing an area of 303,521 km (121,408 mi). The region was divided into geographic subareas designated : Southern New England, New York Bight, and Chesapeake Bight. These subareas (fig. 1) contain 94,700, 82,749, and 126,072 km* (37,880, 33,100, and 50,428 mi), re- spectively. More detailed data on the areal expanse of various subunits within the region are listed in table 2. A nearly equal number of samples came from such subarea: Southern New England-186 samples; New York Bight-187 samples; Chesapeake Bight-190 samples. TABLE 2.-Areas of several bathymetric zones within each subarea and total area of Middle Atlantic Bight region [In square kilometers] Subarea Southern New England 2,674 New York Chesapeake Total Bight Bight 2 3,788 8,035 15,045 17,604 3,228 43,912 Bathymetric zone Bays and Sounds! -_ 17,401 Continental Shelf 0- 12,015 15,488 6,987 1,930 36,420 23,863 25,545 38,786 41,577 9,984 115,892 Total Continental Slope 220- 499 m .___. 500- 999 m ___. 1,000-1,999 m ___.. Total Continental Rise 2,000-3,999 m -__- Grand total ___ 1,129 1,515 38,5141 6,158 1,222 1,813 8,598 11,633 4,204 5,245 15,779 25,228 49,029 94,700 28,891 82,749 60,618 126,072 1 Based on areas reported by Bumpus, Lynde, and Shaw (1973). 2 Includes the Gardiners Bay complex (1,078 km*). 138,538 303,521 N6 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES FIGURE 2.-Chart showing station locations where quantitative samples of macrobenthic invertebrates were obtained. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION BENTHOS SAMPLING GEAR Three different quantitative grab-type bottom samplers were used: the Van Veen grab * (Holme and McIntyre, 1971); the Smith-McIntyre sampler (fig. 3) (Smith and McIntyre, 1954); and the Camp- bell grab (fig. 4) (Menzies, Smith, Emery, 1963). All three are reliable devices for obtaining quanti- tative samples with relative ease under a wide va- riety of working conditions. A small vessel was used in sampling inshore waters, and this restricted the use of bottom samplers to the two smaller ones-V an Veen and Smith-McIntyre. Thirteen samples (2 per- cent), each representing an area of 0.1 m*, were taken with the Van Veen grab; 195 samples (85 per- cent) were taken with a 0.1 m*-size Smith-MecIntyre grab; and 355 (63 percent) samples were taken with the 250-kg Campbell grab, each sample representing an area of 0.56 m*. These devices provided enough material for both biological and geological analyses. The Campbell grab was equipped with an auto- matic camera and electronic light source (Emery, Merrill, Trumbull, 1965; Emery and Merrill, 1964), which provided a photograph of the sea bottom that was taken immediately prior to bottom contact. The camera housing, fastened within one of the buckets of the grab (fig. 4), contained two 35-mm motorized cameras spaced to provide stereo separation, if de- sired. Usually, each camera was loaded with a dif- ferent type of film; one contained black and white negative material and the other reversal (positive), high-speed daylight color film. The opposite bucket held the electronic strobe light that illuminated the area to be photographed. The device was activated at about 1 m above the bottom by means of a trip- weight suspended below the grab. Approximately 200 simultaneous photographs and bottom samples were obtained within the study area. Of this total, 180 photographs were in black and white (examples in figs. 89 to 94) and 20 were in color. SAMPLE PROCESSING Processing of samples depended on the size of the equipment and the method of determining sediment volume. Contents of the grab were emptied into a watertight receptacle large enough to hold all the collected substratum. Substrate receptacles for the Van Veen and Smith-McIntyre samplers were 20- liter graduated pails; the receptacle for the Campbell grab was a large rectangular steel tub, which also served as the washing container. The volume of the 4 Any trade names in this publication are used for descriptive purposes only and do not constitute endorsement by the U.S. Geological Survey. NT samples was determined, prior to any treatment. The graduated pails used with Van Veen and Smith- McIntyre samplers gave a direct reading of volume, and precalibrated brass dipsticks were used to de- termine the volume of Campbell grab samples. Vol- umes were recorded to the nearest whole liter. All samples were washed on a sieving screen having 1-mm mesh openings to remove unwanted sediments and retain specimens. The Van Veen and Smith-McIntyre samples were first washed in a specially designed washstand that had adjustable- flow shower heads trained onto the mound of sedi- ment samples. Waterflow gently flooded the orga- nisms out of the sediments and transported them to the sorting sieve where everything greater than 1 mm in size was retained. The Campbell grab samples were washed in the same receptacle that received the sample. Water from hoses with variable nozzles floated sediments and organisms through openings in the container to the sieving sereens. Coarse substrate fractions, such as pebbles and cobbles, that were retained on the sereen required further treatment. These larger fractions were sorted out by hand and examined. If clean (no at- tached organisms), they were discarded; those with attached organisms were retained for later treat- ment. Organisms and sediments retained by the screen were preserved in a 5 percent buffered sea- water solution of formaldehyde in glass containers, labeled, and stored for transport to the laboratory. Laboratory treatment of preserved specimens in- volved: (1) rinsing in freshwater to flush off formalin solution; (2) sorting and identifying to the lowest accurate taxonomic level; (3) recording counts of individuals in each taxonomic group; and (4) obtain- ing damp or wet weights (excess superficial fluids removed with blotting paper) of each group. In- cluded in the weight measurements are skeletal structures that form an integral part of the living animal. This, of course, includes shells of mollusks, brachiopods, crustaceans, echinoderms, and all other organisms having a shell-like skeleton. Weights do not include hermit crab "houses," amphipod or poly- chaete tubes, or other such accessory structures. After the above treatment, all specimens were pre- served in 70 percent ethanol and stored in labeled containers. DATA REDUCTION Certain adjustments to the raw data were re- quired to make one sample comparable with another. The criterion of comparability chosen was a unit area of 1 m*. Adjustments were made to account for N8 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES fir UP UUU yy , ix M x> ee r J- p3 FicurE 3.-Side view of the Smith-McIntyre spring-loaded bottom sampler in the closed position. Lead weights on each side are set vertically to impede rotation of the sampler during descent and ascent. Vertical distance from frame base to top plate is 52 em. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION NJ FIGURE 4.-Bottom view of Campbell grab sampler. Camera is installed in right-hand bucket and strobe light is in the left-hand bucket. Width of the buckets (vertical dimension in photograph) is 57 cm. N1O sampling gear size (area of bottom sampled) and material removed (such as sediment samples for geological analyses), prior to processing. A MESA (Marine Ecosystems Analysis) for- mated, IBM compatible, magnetic computer tape of benthic data was made and submitted to MESA, New York Bight project office. A major difference between our data processing system and that of MESA's is the coding schemes used to identify the various taxonomic components. The system we (Demersal Food Chain Investigation at the North- east Fisheries Center, Woods Hole, Mass.) used was an 1l1-digit code developed by us in 1962, and it differs substantially from the 10-digit code used by MESA. Our code is divided as follows: Phylum (2 digits); Class (1); Order (2); Family (2); Genus (2); Species (2). At present, our taxonomic code data-file contains approximately 6,000 names from the U.S. east coast. BATHYMETRY Water depths, in meters, were obtained by means of echo sounders and corrected for hydrophone depth and temperature effects on the velocity of sound. TEMPERATURE Owing to a lack of information on bottom-water temperature, especially in the southeastern part of New York Bight and in Chesapeake Bight, a means of determining temperatures was required. Mini- mum and maximum temperatures for each sampling site were obtained from various published sources (see "Introduction") and from measurements ob- tained by the Northeast Fisheries Center. The ranges in temperature were determined by subtracting the minimum from the maximum; they were then grouped into ranges which were used in the tempera- ture analyses. GEOLOGICAL SAMPLES A sample of bottom sediment was collected from each macrobenthic sample. A lithological description was made at the time of collection and was based on field-analysis techniques. The sample was placed in a cardboard container, air-dried, and brought to the laboratory ashore for detailed determination of grain-size composition, a measure of organic carbon, and analyses of other chemical and minerological components by geologists of the U.S. Geological Sur- vey and the Woods Hole Oceanographic Institution. Analysis results are on file in Woods Hole Ocean- ographic Institution Reference No. 71-15, Data File, Continental Margin Program Atlantic Coast of the ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES United States, volumes 1 and 2, compiled and edited by John C. Hathaway, U.S. Geological Survey, Woods Hole, Mass. Data pertaining to bottom sedi- ments and quantity of organic carbon used in our analyses are listed in this document. FAUNAL COMPOSITION ENTIRE MIDDLE ATLANTIC BIGHT REGION The faunal composition in the Middle Atlantic Bight region is moderate-the number of species and higher taxa are neither very abundant nor very sparse. The different species in the samples num- bered 485; they represented 17 phyla. This modest variation in taxonomic diversity is typical of a temperate marine fauna. However, to some extent, the observed variation resulted from our knowledge of particular taxonomic groups and our facility (and that of cooperating scientists) in identifying the components of the various groups. This is evident from the relatively large numbers of species in Arthropoda, Annelida, and Mollusca. Also, our pri- orities in establishing taxonomic work assignments resulted in relatively small effort being devoted to identifying the species composition of the less im- portant (in terms of abundance or biomass) groups, such as Porifera, Platyhelminthes, Hemichordata, Nemertea, and Aschelminthes. In evaluating the total fauna (all taxonomic groups from all samples) , we found that four groups dominated: Arthropoda, Annelida, Mollusca, and Echinodermata. Dominance of these groups was ap- parent in both number and biomass; however, the order of importance differed substantially between the two measures (table 3; fig. 5). Numerical domi- nance, here indicated by mean density per square meter and percentage of the total fauna they con- stituted, was as follows: Arthropoda, 641, (45 per- cent); Mollusca, 346, (25 percent); Annelida, 298, (21 percent); Echinodermata, 55, (4 percent); and all other groups combined, 65, (5 percent). Biomass, which is here expressed as mean wet weight or damp weight in grams per square meter and per- centage of the total fauna, was even more heavily dominated by a few taxonomic groups than was numerical density. Principal components in terms of biomass were: Mollusca, 136, (71 percent); Echino- dermata, 23, (12 percent); Annelida, 14, (7 percent); Arthropoda, 9, (5 percent). Minor groups listed here in order of decreasing biomass were: Chordata, Coelenterata, Sipunculida, Nemertea, Bryozoa, Echiura, Porifera, Hemichordata, Pogonophora, Priapulida, Platyhelminthes, Aschelminthes, and Brachiopoda. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N11 TABLE 3.-Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individuals and biomass, representing the entire Middle Atlantic Bight region Taxonomic group Number of individuals Biomass Phy 1 um Phy 1 um Mean Percent rank Mean Percent rank No./m2 g/m2 PORIFERA 0.56 0.04 13 0.058 0:03 11 COELENTERATA 17.76 1.26 5 2.975 1.56 6 Hydrozoa 9.57 0.68 0.296 0.16 Anthozoa 8.19 0.58 2.680 1.41 Alcyonacea 0.51 0.04 0.091 0.05 Zoantharia 3.81 0.27 2.425 1.27 Unidentified 3.87 0.28 0.164 0.09 PLATYHELMINTHES 0.64 0.05 12 0.007 0.004 15 Turbellaria 0.64 0.05 0.007 0.004 NEMERTEA 4.51 0:32 8 0.619 0. 32 8 ASCHELMINTHES 2.60 0.18 10 0.005 0.002 16 Nematoda 2:60 0.18 0.005 0.002 ANNEL IDA 297.77 21.18 3 13.814 7.24 3 POGONOPHORA 1.91 0.14 11 0.012 0.01 13 SIPUNCUL IDA 3.94 0.28 9 0.689 0.36 7 ECHIURA 0.15 0.01 14 0.249 0.13 10 PRIAPULIDA 0.01 0.001 16 0.009 0.005 14 MOLLUSCA 346.29 24.63 2 136.131 7%. 38 1 Polyplacophora 0.45 0.03 0.144 0.08 Gastropoda 35.79 2.55 2-081 1.62 Bivalvia 308.27 21.93 132.878 69.68 Scaphopoda 1.26 0.09 0.022 <0 .001 Cephalopoda 0:33 0.02 0.004 0.002 Unidentified 0.19 0.01 0.001 <0.001 ARTHROPODA 640.51 45.56 1 9.013 4.73 4 Pycnogon ida 0.54 0.04 0.003 0.002 Arachnida 0.05 0.004 <0 .001 <0.001 Crustacea 639.92 45.52 9.010 4.72 Ostracoda 0.22 0.02 0.002 0.001 Cirripedia 30.02 2. 14 3.747 1.96 Copepoda 0.04 0.003 <0. 001 <0.001 Nebaliacea 0.01 0.001 <0 .001 <0.001 Cumacea 15.92 1:13 0.071 0.04 Tanaidacea 0.06 0.004 <0.001 <0.001 Isopoda 12.31 0. 88 0.290 0.15 Amphipoda 572.09 40.70 3.676 1.93 Mysidacea 2.06 0.15 0.009 0.005 Decapoda 7.19 0.51 1.214 0.64 BRYOZOA 12.22 0.87 7 0.329 0.17 9 BRACHIOPODA <0.01 0.03 17 <0.001 <0 .001 17 ECHINODERMATA 54.64 3.89 4 22.775 11.94 2 Holothuroidea 2.15 0.15 5. 386 2.82 Echinoidea 23.09 1.64 13.641 7-15 Ophiuroidea 28.50 2.03 1.798 0.94 Asteroidea 0.90 0.06 1.949 1.02 HEMICHORDATA 0.13 0.01 15 0.029 0.01 12 CHORDATA 14.69 1.05 6 3.721 1.95 5 Ascidiacea 14.69 1. 05 3.721 1.95 UNIDENTIFIED 7.40 0.53 0.274 0.14 N12 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES ARTHROPODA 45.6% NUMBER OF INDIVIDUALS 2 F 2 % m A ® p m ye i é \ & ANNELIDA 21.2% o >: & (9 e mY of, V SEBH‘LO 1—‘b’ BIOMASS FIGURE 5.-Pie charts illustrating the taxonomic composition of the total macrobenthic fauna in the entire Middle Atlantic Bight region. Number of individuals expressed as a per- centage of the total fauna; and biomass, also expressed as a percentage of the total. Because of the exceptionally large biomass formed by Mollusca, we would like to focus attention on the biomass determination procedures. It has long been standard practice to obtain wet weight biomass values by weighing the entire animal-including shells and all other intregal body parts (Thorson, 1957). This, of course, is to provide consistency in dealing with enormously varied taxonomic assem- MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION blages that have different proportions of skeletal structures and water content, both of which are ex- ceedingly low in nutritive value. Some of the Echi- noidea, Cirripedia, and other groups possess higher proportions of skeletal structure than mollusks; Brachiopods, Brachyurans, and other groups gen- erally have about the same or slightly smaller pro- portions of skeletal structure than mollusks; and many Holothuroidea, Annelida, and other soft- bodied groups commonly have a very small propor- tion of skeletal structure. Water content also varies substantially from group to group, and is particu- larly high in Ascidiacea and some Coelenterata. Be- cause of these and other variations in body compo- sition, measures other than wet weight biomass must be used to show nutrient value. For purposes of energy pathway studies and dynamic modeling, ecologists often require measures of energy, such as caloric value. Our determinations of conversion coefficients for converting wet weights to dry weights are incom- plete at present. However, by using our conversion values supplemented by values obtained from pub- lished reports, we made a preliminary comparison of the percentage composition of the macrobenthic fauna in terms of wet weight and calculated ash- free dry weight. Only modest differences in relative standing of the taxonomic groups were revealed by this comparison. Thus, the major biomass position occupied by mollusks in this region results from their relatively large size combined with rather high numerical abundance. Dominance of the fauna by a relatively few groups of organisms was also apparent at more specific taxonomic levels-genera and species. In the taxo- nomic list of species given in table 4 are 441 species that were represented in samples within the Middle Atlantic Bight region. Of this number, less 10 per- cent are considered important in terms of number and (or) biomass. In number of specimens, some of the more important forms were: Scalibregma, Nephtys, Maldane, Sabella, Spiophanes (Annelida); Alvania, Cylichna, Nassarius (Gastropoda); Nucula, Cyclocardia, Astarte, Thyasira (Bivalvia); Balanus (Cirripedia); Trichophozus, Leptocheirus, Ampe- lisca, Unciole (Amphipoda); Cirolana (Isopoda); Echinarachnius (Echinoidea). Important as major contributors to the biomass were: Cerianthus (Coelenterata); Nephtys, Streb- losoma, Maldane, Lumbrineris (Annelida); Arctica, Astarte, Cyclocardia, Mulinia, Emsis (Bivalvia) ; Buccinum, Nassarius (Gastropoda); Trichophozus, N13 TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region Coelenterata (Cnidaria) Hydrozoa Hydractinia echinata Fleming, 1828 Anthozoa Alcyonacea Pennatula aculeata Danielson and Koren, 1858 Zoantharia Zoanthidea Epizoanthus incrustatus (Verrill) 1864 Actiniaria Anthaloba perdix Verrill, 1882 Edwardsia sp. Haliplanella luciae (Verrill) 1898 Haloclava producta Stimpson, 1856 Paranthus rapiformis Lesueur, 1817 Madreporaria Astrangia danae Agassiz, 1847 Ceriantharia Cerianthus borealis Verrill, 1873 Ceriantheopsis americanus Verrill, 1866 Annelida Polychaeta Phyllodocida Phyllodocidae Eteone sp. Eumida sanguinea (Oersted) 1843 Phyllodoce arenae Webster, 1879 Phyllodoce mucosa Oersted, 1843 Phyllodoce sp. Aphroditidae Aphrodita hastata Moore, 1905 Polynoidae Harmothoe extenuata (Grube) 1840 Sigalionidae Lean-ira sp. Pholoe minuta (Fabricius) 1780 Sigalion arenicola Verrill, 1879 Sthenelais limicola (Ehlers) 1864 Glyceridae Glycera americana Leidy, 1855 Glycera capitata Oersted, 1843 Glycera dibranchiata Ehlers, 1868 Glycera robusta Ehlers. 1868 Glycera tesselata Grubé, 1863 Goniadidae Goniada brunnea Treadwell, 1906 Goniada maculata (Oersted) 1843 Goniadella gracilis {Verrill) 1873 Sphaerodoridae Sphaerodorum gracilis (Rathke) 1843 Nephtyidae Aglaophamus cireinata (Verrill) 1874 Aglaophamus sp. Nephtys bucera Ehlers, 1868 Nephtys incisa Malmgren, 1865 Nephtys picta Ehlers, 1868 Syllidae Exogone verugera (Clarapede) 1868 Pilgaridae Ancistrosyllis sp. Nereidae Ceratocephale loveni Malmgren, 1867 Nereis pelagica Linnaeus, 1758 Nereis sp. Capitellida Capitellidae Capitella sp. Scalibregmidae Scalibregma inflatum Rathke, 1843 Maldanidae Asychis biceps (Sars), 1861 Maldane sp. Opheleidae Ammotrypane aulogaster Rathke, 1843 Ammotrypane sp. Ophelia denticulata Verrill, 1875 Travisia sp. N14 TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region- Continued Annelida-Continued Polychaeta-Continued Sternaspida Sternaspidae Sternaspis scutata (Renier) 1807 Spionida Spionidae Dispio uncinata Hartman, 1951 Laonice cirrata (Sars) 1851 Prionospio sp. Polydora concharum Verrill, 1880 Polydora sp. Spio setosa Verrill, 1873 Spiophanes bombyx (Clarapede) 1870 Paraonidae Aricidea jeffreysii (McIntosh) 1879 Paraonis fulgens (Levinsen) 1883 Paraonis neapolitana Cerruti, 1909 Chaetopteridae Chaetopterus sp. Spiochaetopterus sp. Eunicida Onuphidae Diopatra cuprea (Bose) 1802 Hyalinoecia tubicola (Miller) 1776 Onuphis conchylega Sars, 1835 Onuphis eremita Audoin and Milne- Edwards, 1833 Onuphis opalina (Verrill) 1873 Onuphis quadricuspis Sars, 1872 Paradiopatra sp. Eunicidae Eunice pennata (Miiller) 1776 Marphysa belli (Audoin and Milne- Edwards) 1883 Lumbrineridae Lumbrineris ceut« (Verrill) 1875 Lumbrineris fragilis (Miiller) 1776 Lumbrineris tenuis (Verrill) 1873 Ninoe nigripes Verrill, 1873 Arabellidae Arabella tricolor (Montagu) 1804 Drilonereis longa Webster, 1879 Notocirrus sp. Amphinomida Amphinomidae Paramphinome pulchella Sars, 1872 Magelonida Magelonidae Magelona sp. Ariciida Orbiniidae Orbinia ornata (Verrill) 1873 Orbinia swani Pettibone, 1957 Scoloplos robustus (Verrill) 1873 Cirratulida Cirratulidae Chaetozone sp. Cirratulus sp. Cossura longocirrata Webster and Benedict, 1883 Tharyx sp. Oweniida Oweniidae Owenia fusiformis delle Chiaje, 1844 Terebellida Pectinariidae Pectinaria gouldii (Verrill) 1873 Ampharetidae Ampharete acutifrons (Grube) 1860 Ampharete arctica Malmgren, 1866 Asabellides oculata Webster, 1879 Melinna cristata (Sars) 1851 Terebellidae Amphitrite sp. Streblosoma spiralis (Verrill) 1874 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region- Continued Annelida-Continued Polychaeta-Continued Flabelligerida Flabelligeridae Brada sp. Flabelligera sp. Pherusa sp. Sabellida Sabellidae Chone infundibuliformis Kroyer, 1856 Euchone sp. Potamilla reniformis (Linnaeus) 1788 Sabella sp. POGONOPHORA Oligobrachiidae Oligobrachia floridana Nielsen, 1965 Siboglinidae Siboglinum angustum Southward and Brattegard, 1968 Siboglinum bayeri Southward, 1971 Siboglinum ekmani Jagerston, 1956 Stboglinum gosnoldae Southward and Brattegard, 1968 Siboglinum holmei Southward, 1963 Siboglinum longicollum Southward and Brattegard, 1968 Siboglinum pholidotum Southward and Brattegard, 1968 Polybrachiidae Crassibrachia sandersi Southward, 1968 Diplobrachia similis Southward and Brattegard, 1968 Diplobrachia sp. Polybrachia lepida Southward and Brattegard, 1968 Polybrachia sp. SIPUNCULIDA Aspidosiphon spinalis Ikeda, 1904 Aspidosiphon zinni Cutler, 1969 Golfingia catharinae Miiller, 1789 Golfingia constricticervix Cutler, 1969 Golfingia elongata (Keferstein) 1869 Golfingia eremita (Sars) 1851 Golfingia flagrifera (Selenka) 1885 Golfingia margaritacea (Sars) 1851 Golfingia minuta (Keferstein) 1865 Golfingia murinae murince Cutler, 1969 Golfingia trichocephala (Sluiter) 1902 Onchnesoma steenstrupi Koren and Danielsson, 1875 Phascolion strombi (Montague) 1804 Sipunculus norvegicus Koren and Danielsson, 1875 ECHIURA Bonellidae Bonellia thomensis Fisher, 1922 Ikedella achaeta (Zenkevitch, 1958) Prometor grandis (Zenkevitch, 1957) Sluiterina sibogae (Sluiter, 1902) Sluiterina sp. MOLLUSCA Gastropoda Prosobranchia Archaegastropoda Acmaea testudinalis (Miiller) 1776 Calliostoma bairdi Verrill and Smith, 1880 Calliostoma occidentale (Mighels and Adams) 1842 Mesogastropoda Alvania brychia (Verrill) 1884 Alvania carinata Mighels and Adams, 1842 Crepidula fornicata Linnaeus, 1767 Crepidula plana Say, 1822 Crucibulum striatum Say, 1824 Epitonium dallianum Verrill and Smith, 1880 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region- Continued N15 TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region- Continued Mollusca-Continued Gastropoda-Continued Prosobranchia-Continued Mesogastropoda-Continued Epitonium greenlandicum (Perry) 1811 Epitonium multistriatum (Say) 1826 Fossarus elegans Verrill and Smith, 1882 Lunatia heros (Say) 1822 Lunatia triseriata (Say) 1826 Melanella intermedia (Cantraine) 1835 Natica clausa Bowderup and Sowerby, 1829 Natica pusilla Say, 1822 Polinices duplicatus (Say) 1822 Polinices immaculatus (Totten) 1885 Turritellopsis acicula (Stimpson) 1851 Neogastropoda Anachis sp. Buccinum undatum Linnaeus, 1758 Busycon carica (Gmelin) 1791 Colus pubescens Verrill, 1882 Colus pygmaeus (Gould) 1841 Eupleura caudata (Say) 1822 Mitrella lunata (Say) 1826 Mitrella zonalis Gould, 1848 Nassarius trivittatus (Say) 1822 Neptunez decemcostata (Say) 1826 Taranis cirrata (Brugnone) 1822 Euthyneura Pyramidelloida Odostomia gibbosa Bush, 1909 Turbonilla interrupta (Totten) 1835 Cephalapsida Cylichna alba (Brown) 1827 Cylichna gouldi (Couthouy) 1839 Haminoea solitaria (Say) 1822 Retusa obtusa (Montagu) 1807 Scaphander punctostriatus Mighels, 1841 Notapsida Pleurobranchia tarda Verrill, 1880 Bivalvia Paleotaxodonta Nuculoida Nuculidae Nuculza delphinodonta Mighels and Adams, 184 Nucula proxima Say, 1822 Nucula tenuis Montagu, 1808 Malletiidae Malletia obtusata G.O. Sars, 1872 Nuculanidae Nuculana acuta (Conrad) 1831 Nuculana tenuisulcata (Couthouy) 1838 Portlandia inflata (Verrill and Bush) 1897 Portlandia iris (Verrill and Bush) 1897 Yoldia limatula (Say) 1831 Yoldia sapotilla (Gould) 1841 Cryptodonta Solemyoida Solemyacidae Solemya velum Say, 1822 Pteriomorphia Arcoida Arcidae Anadara ovalis (Brugiere) 1789 Bathyarca anomala (Verrill and Bush) 1898 Bathyarca pectunculoides (Scacchi) 1833 Limopsidae Limopsis minuta Philippi, 1836 Limopsis sulcata Verrill and Bush, 1898 Mytiloida Mytilidae Crenella decussata (Montagu) 1808 Crenella glandula (Totten) 1834 Crenella pectinula (Gould) 1841 Dacrydium vitreum (Holboll and Miiller) 1842 Modiolus modiolus (Linnaeus) 1758 Bivalvia-Continued Pteriomorphia-Continued Mytiloida-Continued Mytilidae-Continued Musculus corrugatus (Stimpson) 1851 Musculus discors (Linnaeus) 1767 Musculus niger (Gray) 1824 Mytilus edulis Linnaeus, 1758 Pteroidea Pectinidae Aequipecten glyptus (Verrill) 1882 Pecten thalassinus Dall, 1886 Placopecten magellanicus (Gmelin) 1791 Anomiidae Anomia aculeata Linnaeus, 1758 Anomia simplex Orbigny, 1842 Limidae Limatula subauriculata (Montagu) 1808 Heterodonta Veneroida Lucinidae Lucinoma filosa (Stimpson) 1851 Leptonidae Aligena elevata (Stimpson) 1851 Thyasiridae Thyasira ferruginosa Forbes, 1844 Thyasira flexuosa (Montagu) 1803 Thyasira ovata Verrill and Bush, 1898 Thyasira pygmaea Verrill and Bush, 1898 Thyasira trisinuata Orbigny, 1842 Carditidae Cyclocardia borealis (Conrad) 1831 Astartidae Astarte borealis (Schumacher) 1817 Astarte castanea (Say) 1822 Astarte elliptica (Brown) 1827 Astarte quadrans Gould, 1841 Astarte subequilatera Sowerby, 1854 Astarte undata Gould, 1841 Cardiidae Cerastoderma pinnulatum (Conrad) 1831 Laevicardium mortoni (Conrad) 1830 Mactridae Mulinia lateralis (Say) 1822 Spisula solidissima (Dillwyn) 1817 Solenidae Ensis directus Conrad, 1843 Siliqua costata Say, 1822 Tellinidae Macoma balthica (Linnaeus) 1758 Macoma tenta (Say) 1834 Tellina agilis Stimpson, 1857 Semelidae Abra longicallis Verrill and Bush, 1898 Arcticidae Arctica islandica (Linnaeus) 1767 Veneridae Liocyma fluctuosa (Gould) 1841 Mercenaria mercenaria (Linnaeus) 1758 Pitar morrhuanus Linsley, 1848 Mesodesmatidae Mesodesma arctatum (Conrad) 1830 Petricolidae Petricola pholadiformis (Lamarck) 1818 Myoida Myidae Mya arenaria Linnaeus, 1758 Corbulidae Corbula contracta Say, 1822 Hiatellidae Cyrtodaria siliqua (Spengler) 1793 Hiatella arctica (Linnaeus) 1767 Panomya arctica (Lamarck) 1818 Analodesmacea Pholadomyoida Lyonsiidae Lyonsia hyalina Conrad, 1831 N16 TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region- Continued ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region- Continued Bivalvia-Continued Analodesmacea-Continued Pholadomyoida-Continued Pandoridae Pandora gouldiana Dall, 1886 Pandora inflata Boss and Merrill, 1965 Pandora inornata Verrill and Bush, 1898 Thraciidae Thracia conradi Couthouy, 1838 Thracia myopsis (Miller) 1842 Periplomatidae Periploma afinis Verrill and Bush, 1898 Periploma fragile (Totten) 1835 Periploma leanum (Conrad) 1831 Periploma papyratium (Say) 1822 Septibranchoida Poromyidae Poromya granulata (Nyest and Westendorp) 18839 Cuspidariidae Cardiomya perrostrata Dall, 1881 Cardiomya striata (Jeffreys) 1876 Cuspidaria parva Verrill and Bush, 1898 Myonera limatula Dall, 1881 Scaphopoda Cadulus pandionis Verrill and Smith, 1880 Cadulus verrilli Henderson, 1920 Dentalium occidentale Stimpson, 1851 ARTHROPODA Pyenogonida Achelia spinosa (Stimpson) 1853 Anoplodactylus parvus Giltay, 1934 Nymphon sp. Crustacea Ostracoda Cycloberis sp. Pseudophilomedes ferulanus Kornicker, 1959 Cirripedia Balanus balanus (Linnaeus) 1758 Balanus crenatus Brugiere, 1789 Balanus venustus niveus Darwin, 1854 Nebaliacea Cumacea Diastylis polita S.I. Smith, 1879 Diastylis quadrispinosa G.O. Sars, 1871 Diastylis sculpta G.0. Sars, 1871 Eudorella emarginata (Kroyer) 1846 Eudorellopsis sp. Leptostylis sp. Petalosarsia declivis (G.C. Sars) 1864 Tanaidacea Anorthura sp. Neotanais sp. Isopoda Calathura sp. Chiridotea arenicola Wigley, 1960 Chiridotea tuftsi (Stimpson) 1883 Cirolana polita (Stimpson) 1853 Cyathura polita (Stimpson) 1855 Edotea triloba (Say) 1818 Erichsonella filiformis (Say) 1818 Idotea sp. Ptilanthura tenuis Harger, 1879 Amphipoda Gammaridea Gammaridae Gammarus annulatus Smith, 1873 Gammarus mucronatus Say, 1818 Gammarus palustris Bousfield, 1969 Crangonycidae Crangonyx pseudogracilis Bousfield, 1958 Melitidae Casco bigelowi (Blake) 1929 Elasmopus levis Smith, 1873 Maera danae Stimpson, 1853 Maera loveni (Bruzelius) 1859 Amphipoda-Continued Gammaridea-Continued Melita dentata (Kroyer) 1842 Melita palmata (Montagu) 1894 Haustoriidae Acanthohaustorius millsi Bousfield, 1965 Amphiporeia virginiana Shoemaker, 1933 Bathyporeia parkeri Bousfield, 1973 Bathyporeia quoddyensis Shoemaker, 1949 Protohaustorius wigleyi Bousfield, 1965 Pseudohaustorius borealis Bousfield, 1965 Phoxocephalidae Harpinia propingqua Sars, 1895 Phoxocephalus holbolli Kréyer, 1842 Trichophoxis epistomus (Shoemaker) 1938 Pontogeneidae Pontogeneia inermis (Kroyer) 1842 Pleustidae Stenopleustes gracilis (Holmes) 1905 Stenopleustes inermis Shoemaker, 1949 Ampeliscidae Ampelisca abdita Mills, 1967 Ampelisca aequicornis Bruzelius, 1859 Ampelisca agassizt Judd, 1896 Ampelisca macrocephala Liljeborg, 1852 Ampelisca vadorum Mills, 1963 Ampelisca verrilli Mills, 1967 Byblis gaimardi (Kroyer) 1846 Byblis serrata Smith, 1873 Liljeborgiidae Liljeborgia sp. Listriella sp. Lysianassidae Anonyx liljeborgi Boeck, 1870 Anonyx sp. Hippomedon propinguus Sars, 1870 Hippomedon serratus Holmes, 1905 Orchromenella groenlandica (Hansen) 1887 Orchromenella pinquis (Boeck) 1861 Psammonyx nobilis (Stimson) 1853 Aoridae Lembos sp. Leptochetrus pinguis (Stimpson) 1853 Leptocheirus plumulosus Shoemaker, 1932 Pseudunciola obliquua (Shoemaker) 1949 Unciola inermis Shoemaker, 1942 Unciola irrorata Say, 1818 Unciola leucopis (Kroyer) 1845 Photidae Photis macrocoxa Shoemaker, 1945 Photis reinhardi Kroyer, 1842 Protomedia fasciata Kroyer, 1842 Ischyroceridae Ischyrocerus anguipes Kroyer, 1838 Corophiidae Cerapis tubularis Say, 1818 Corophium insidiosum Crawford, 1937 Corophium volutator (Pallas) 1766 Corophium sp. Erichthonius brasiliensis (Dana) 1853 Erichthonius rubricornis Smith, 1873 Siphonoectes smithianus Rathbun, 1908 Podoceridae Dulichia porrecta (Bate) 1857 Caprellidea Caprellidae Aeginina longicornis (Kréyer) 1842-43 Caprella penantis Leach, 1814 Caprella septentrionalis Kroyer, 1838 Caprella unica Mayer, 1903 Caprella sp. Luconatia incerta Mayer, 1903 Mysidacea Bowmaniella portoriciensis Bacescu, 1968 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region- Continued ARTHROPODA-Continued Amphipoda-Continued Mysidacea-Continued Erythrops erythropthalma (Goes) 1864 Heteromysis formosa S.I. Smith, 1873 Mysidopsis bigelowi Tattersall, 1926 Neomysis americana (S.1. Smith) 1873 Promysis atlantica Tattersall, 1923 Decapoda Caridea Crangon septemspinosus Say, 1818 Dichelopandalus leptocerus (Smith) 1881 Anomura Axius serratus Stimpson, 1852 Callichirus atlanticus (Smith) 1874 Munida sp. Pagurus acadianus Benedict, 1901 Pagurus arcuatus Squires, 1964 Pagurus pubescens (Kroyer) 1838 Upogebia affinis (Say) 1817 Brachyura Cancer borealis Stimpson, 1859 Cancer irroratus Say, 1817 Hyas coarctatus Leach, 1815 Libinia emarginata Leach, 1815 Ocypode quadrata (Fabricius) 1787 Pinniza sayana Stimpson, 1860 BRYOZOA Ctenostomata Alcyonidiidae Alcyonidium sp. Cyclostomata Crisiidae Crisia eburnea (Linnaeus) 1758 Cheilostomata Serupraridae Eucratea loricata (Linnaeus) 1758 Haplota clavata (Hincks) 1857 Membraniporidae Conopeum reticulum (Linnaeus) 1767 Membranipora tenuis Desor, 1848 Membranipora tuberculata (Bosc) 1802 Electridae Electra hastingsae Marcus, 1938 Electra pilosa (Linnaeus) 1767 Calloporidae Amphiblestrum flemingii (Bush) 1854 Callopora aurita (Hincks) 1877 Callopora lineata {(Linnaeus) 1767 Bugulidae Bugula turrita (Desor) 1848 Dendrobeania murrayana (Johnston) 1847 Cribrilinidae Cribrilina punctata (Hassall) 1841 Schizoporellidae Schizoporella unicornis (Johnston) 1847 Microporellidae Microporella ciliata (Pallas) 1766 Hippoporinidae Hippoporina americana (Verrill) 1875 Hippoporina porosa (Esper) 1796 Smittinidae Rhamphostomella costata Lorenz, 1886 Cheiloporinidae Cryptosula palasiana (Moll) 1803 ECHINODERMATA Holothuroidea Dendrochirodota Cucumaria planet Marenzeller, 1893 Havelockia seabra (Verrill) 1873 Psolus fabricii (Duben and Koren) 1846 Stereoderma unisemita (Stimpson) 1851 Thyone fusus (Miller) 1788 Apodida Chirodota wigleyi Pawson, 1976 Synapta sp. N17 TABLE 4.-Invertebrate species contained in quantitative samples taken within the Middle Atlantic Bight region- Continued ECHINODERMATA-Continued Holothuroidea-Continued Molpadiida Caudina arenata Gould, 1841 Molpadia musculus Risso, 1826 Molpadia colitica (Pourtales) 1857 Echinoidea Cideroidea Stylocidaris affinis Phillips, 1845 Arbacioidea Arbacia punctulata (Lamarck) 1816 Temnopleuroidea Genocidaris maculata Agassiz, 1869 Clypeasteroidea Echinarachnius parma (Lamarck) 1816 Emcope sp. Mellita quinquiesperforata (Leske) 1778 Spatangoidea Aceste bdellifera Wyville Thompson, 1877 Aeropsis rostrata Norman, 1876 Brisaster fragilis (Duben and Koren) 1844 Brissopsis atlantica Mortensen, 1907 Echinocardium cordatum Pennant, 1777 Schizaster orbignyanus A. Agassiz, 1883 Ophiuroidea Ophiuridae Ophiocten scutatem Koehler, 1896 Ophiocten sericeum (Forbes) 1852 Ophiomusium lymant Thompson, 1873 Ophiura acenata Ophiura ljungmani (Lyman) 1878 Ophiura sarst Liitken, 1858 Ophiocanthidae Amphilimna olivacea (Lyman) 1869 Ophiactidae Ophiopholus aculeata (Linnaeus) 1788 Amphiuridae Amphioplus abdita (Verrill) 1872 Amphioplus tumidus (Lyman) 1878 Amphiura fragilis (Verrill) 1885 Amphiura otteri Ljungman, 1871 Axiognathus squamatus (delle Chiaje) 1828 Micropholis atra Amphilepidae Amphilepis ingolfiana Mortensen, 1933 Asteroidea Asterias forbesii (Desor) 1848 Asterias vulgaris Verrill, 1866 Astropecten americana (Verrill) 1880 Astropecten articulatus Say, 1825 Leptasterias sp. HEMICHORDATA Enteropneusta Balanoglossus sp. CHORDATA Ascidiacea Bostrichobranchus pilularis (Verrill) 1871 Ciona intestinalis (Linnaeus) 1767 Cnemidocarpa mollis (Stimpson) 1852 Craterostigma singulare (Van Name) 1912 Molgula citrina Adler and Hancock, 1848 Molgula complanata Alder and Hancock, 1870 Molgula siphonalis Sars, 1859 Leptocheirus, Unciole (Amphipoda); Cancer (De- capoda); Cirolana (Isopoda); Astropecten (Aster- oidea); Echinarachnius, Brisaster (Echinoidea). SUBAREA DIFFERENCES IN COMPOSITION The macrobenthic fauna in all three subareas of the Middle Atlantic Bight region was dominated by the same four major taxonomic groups-Arthropoda, N18 Mollusca, Annelida, and Echinodermata (tables 5, 6, 7; and fig. 6). However, there were pronounced variations in absolute and proportional quantities within these groups. Number of individuals.-Striking diversity in pro- portional makeup of the fauna was evident in all four dominant taxonomic groups. Arthropoda were particularly abundant in Southerr New England, where they constituted 62 percent of the total num- ber of specimens. Southward, they decreased in nearly equal amounts, and accounted for 42 percent of the total fauna in New York Bight and 21 per- cent in Chesapeake Bight. Nearly the opposite trend was seen in the abundance of Mollusca. In Southern New England, they accounted for about 10 percent of the number of animals, but increased southward to 18 percent in New York Bight and 57 percent in Chesapeake Bight. Annelida showed & somewhat dif- ferent trend in percentage composition. They formed approximately equal proportions in Southern New England (18 percent) and Chesapeake Bight (15 percent), but constituted a substantially larger pro- portion of the fauna in New York Bight (83 per- cent). Echinodermata made up a moderately small (2-5 percent) share of the fauna in all areas, but the number present in Southern New England (4.6 percent of the total fauna) and in New York Bight (4.2 percent) was double the proportion present in Chesapeake Bight (2.3 percent). Biomass.-Proportional composition of the bio- mass was more consistent than the number of speci- mens from one subarea to another. Furthermore, the components had a different order of dominance. Mollusca constituted 64 percent of the biomass in both Southern New England and Chesapeake Bight, and the extra-ordinarily high quantity of 80 percent in New York Bight. Echinodermata ranked second and had roughly equal proportions, between 11 and 13 percent in all subareas. Annelida ranked third and accounted for 9 percent of the biomass in South- ern New England, 5 percent in New York Bight, and 10 percent in Chesapeake Bight. Arthropoda, which ranked first in number of specimens, ranked fourth in biomass. They were substantially more important in Southern New England (where they formed 7.5 percent of the fauna) than in the two more southern subareas where they made up 8.2 and 3.1 percent of the biomass, respectively. Mis- cellaneous taxonomic groups (Ascidiacea, Coelente- rata, Bryozoa, Nemertea, and nine additional groups) were moderately important in Southern ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES New England (6.9 percent) and Chesapeake Bight (10.0 percent), whereas in New York Bight they accounted for only 1.3 percent of the biomass. The relationship between faunal composition and geographic distribution, water depth, bottom sedi- ments, sediment organic content, and water tem- perature are analyzed in subsequent sections. Quan- titative geographic distribution of dominant faunal components is discussed in the section "Dominant Faunal Components." GEOGRAPHIC DISTRIBUTION Before ecological communities or associations of a particular region can be ascertained, the distribu- tion of the important taxonomic groups in that re- gion must be known. The graphic presentation, in the form of charts, of the quantitative geographic distribution of various major taxonomic components of the benthic fauna is one of the more useful methods of expressing quantitative occurrence for the purpose of deter- mining ecological communities. Throughout this re- port where the phrase "major taxonomic compo- nent" is used, we are referring to the higher taxa- phyla, classes, and orders-as listed in tables 12 and 13. The charts permit the reader to visually inte- grate relationships between other organisms and between the numerous abiotic factors that may in- fluence the occurrence of a particular species or faunal group. With these aspects in mind, we pre- pared two quantitative distribution charts for each major taxonomic group found in the Middle Atlantic Bight region. One chart presents the number of individuals (density) and the second presents their weight (biomass); both are expressed in terms of 1m of bottom area. TOTAL MACROBENTHIC FAUNA OF ALL TAXONOMIC GROUPS The density distribution of benthic animals, all taxonomic groups combined, in the Middle Atlantic Bight region showed two major trends. One trend pertains to density in relation to inshore-offshore location. High densities generally prevailed in the coastal areas, moderate densities on the Continental Shelf, and low densities in the offshore, deep waters. A second trend in density distribution pertains to latitudinal differences. In the northern part of the Middle Atlantic Bight region, especially those areas off southern Massachusetts and Rhode Island, there are extensive tracts where the density of benthic animals was high (greater than 1,000/m*) or very MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION ARTHROPODA 61.7% ANNELIDA 33,0% ARTHROPODA 41.8% MOLLUSCA 18.4% “momma?“ _ SH3HLO ANNELIDA 14.8% ARTHROPODA 211% MOLLUSCA 57.3% NUMBER OF INDIVIDUALS he ARTHROGPODA 753; ¢ e MOLLUSCA 63.6% Southern New England MOLLUSCA 79.6% New York Bight MOLLUSCA 64,4 % \ Chesapeake Bight BIOMASS FiGurE 6.-Pie charts illustrating the taxonomic composition of the total macrobenthic fauna for each subarea in the Middle Atlantic Bight region. Numbers of individuals are shown on the left side, and biomasses are shown on the right side. The area of each circle is proportional to the mean density or mean biomass. N19 N20 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 5.-Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individuals and iomass, representing the Southern New England subarea Taxonomic group Number of individuals Biomass Phy 1 um Phylum Mean Percent rank Mean Percent rank No. /me g/m2 PORIFERA 0.75 0.04 13 0:113 0.05 10 COELENTERATA 29.26 1.50 6 4.617 2.19 6 Hydrozoa 14.52 0.74 0.624 0. 30 Anthozoa 14.74 0.75 3.993 1.90 Alcyonacea 0. 80 0.04 0. 165 0.08 Zoantharia 6.31 0.32 3.566 1.69 Unidentified 7.63 0. 39 0.262 0.12 PLATYHELMINTHES 1.46 0.07 11 0.012 0.01 14 Turbellaria 1.46 0.07 0.012 0.01 NEMERTEA 5.99 0.31 10 0.781 0.37 8 ASCHELMINTHES 6.06 0.31 9 0.007 <0.01 16 Nema toda 6.06 0.31 0.007 <0.01 ANNEL IDA 343.92 17.60 2 19.051 9.05 3 POGONOPHORA 1.27 0.06 12 0.009 <0.01 15 SIPUNCULIDA 9.31 0.48 8 1.369 0.65 7 ECHIURA 0.09 <0.01 15 0.051 0.02 11 PRIAPULIDA 0.03 0.01 16 0.021 0.01 13 MOLLUSCA 193.67 9.91 3 133.869 63.58 1 Polyplacophora 1.06 0.05 0.428 0.20 Gastropoda 29:75 72-03 3.489 1.66 Bivalvia 150. 40 7.69 129.924 61.70 Scaphopoda 0.90 0.05 0.014 <0.01 Cephalopoda 0.99 0.05 0.013 «0.01 Unidentified 0.57 0.03 0.002 <0.01 ARTHROPODA 1206.10 61.71 1 15.746 7.48 4 Pycnogonida 0.49 0.03 0.002 <0. 01 Arachnida - - - - Crustacea 1205.61 61.68 15.744 7.48 Ostracoda 0. 32 0.02 0.002 <©.01 Cirripedia 20.57 1.05 7.339 3.49 Copepoda 0.09 <0.01 0.001 <0 .01 Nebaliacea - - - - Cumacea 29.00 1.48 0.135 0.06 Tanaidacea 0.11 <0.01 0.001 <0.01 Isopoda 9.76 0.50 0.218 0.10 Amphipoda 1136.87 58.17 7.023 3.34 Mysidacea 1.34 0:07 0.009 <0.01 Decapoda 7.55 0.39 1.017 0.48 BRYOZOA 26.47 1. 35 vi 0.774 0. 37 9 BRACHIOPODA - - - ECHINODERMATA 90.00 4.60 4 27.216 12.95 2 Holothuroidea 4.83 0.25 14.038 6.67 Echinoidea 9.97 0.51 6.397 3.04 Ophiuroidea 73.39 3. 76 4.612 2.19 Asteroidea 1.81 0.09 2.231 1.06 HEMICHORDATA 0.27 0.01 14 0.050 0.02 12 CHORDATA Je-.19 1.64 5 6.364 3.02 5 Ascidiacea 32.13 1.64 6.364 3.02 UNIDENTIFIED 7x75 0.40 0.445 0.21 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N21 TABLE 6.-Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individuals and biomass, representing the New York Bight subarea Taxonomic group Number of individuals Biomass Phy 1 um Phylum Mean Percent rank Mean Percent rank No.(m2 g/m2 PORIFERA 0.53 0.04 11 0.027 0.01 11 COELENTERATA 8.82 0.74 5 1.386 0.50 5 Hydrozoa 4.42 0.37 0.064 0.02 Anthozoa 4.40 0.37 1.321 0.50 Alcyonacea 0.62 0.05 0.064 0.02 Zoantharia 3.11 0.26 1.166 0.42 Unidentified 0.67 0.06 0.092 0.03 PLATYHELMINTHES 0.06 0.01 15 0.003 «0.01 14 Turbellaria 0.06 0.01 0.003 <0 .01 NEMERTEA 2.665 0.22 8 0.740 o. 27 6 ASCHELMINTHES 0.13 0.01 13 0.001 <0.01 15 Nema toda 0.13 0.01 0.001 <0 .01 ANNEL IDA 391.67 33.00 2 13.393 4.88 3 POGONOPHORA 0. 84 0.07 10 0.004 <0 .01 13 SIPUNCULIDA 2.00 0.17 9 0.324 0.12 7 ECHIURA 0.18 0.02 12 0.282 0.10 9 PRIAPUL IDA - - - MOLLUSCA 218.98 18.45 3 218.634 79.60 1 Polyplacophora 0.06 0.01 0.001 <0.01 Gastropoda 22.01 1.85 2.392 0.86 Bivalvia 195.32 16.46 216.253 78.74 Scaphopoda 1.59 0.13 0.028 0.01 Cephalopoda - - - - Unidentified - - - - ARTHROPODA 496.15 41.81 1 8.719 317 4 Pycnogonida 0.06 0.01 0.001 <0.01 Arachnida 0.14 0.01 0.001 <0 .01 Crus tacea 495.95 41.79 8.217 3.17 Ostracoda 0.28 0.02 0.002 <0.01 Cirripedia 69.75 5. 88 3.979 1.456 Copepoda 0.02 <0.01 <0.001 <0.01 Nebaliacea 0.01 <0.01 <0.001 <0.01 Cumacea 8.58 0.72 0.045 0.02 Tanaidacea 0.02 <0. 01 <0. 001 <0.01 Isopoda 10.58 0.89 0.356 0.13 Amphipoda 396.58 33.42 2.547 0.93 Mysidacea 0.95 0.08 0.005 <0 .01 Decapoda 9.18 0.77 1.782 0.65 BRYOZOA 4 93 0.42 7 0.103 0.04 10 BRACKHIOPODA - ECHINODERMATA 49 48 4.17 4 30.446 11.09 2 Holothuroidea 0.86 0.07 0.513 0.19 Echinoidea 40.24 3.39 25.801 9.39 Ophiuroidea 1.66 0.65 0.552 0.20 Asteroidea 0.72 0.06 3.581 1.30 HEMICHORDATA 0.07 0.01 14 0.004 <0. 01 12 CHORDATA 5.43 0.46 6 0. 340 0.12 8 Ascidiacea 5.43 0.46 0. 340 0.12 UNIDENTIFIED 4.81 0.41 0.245 0.09 N22 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 7.-Quantitative taxonomic composition of the macrobenthic invertebrate fauna, in both number of individuals and biomass, representing the Chesapeake Bight subarea Taxonomic group Number of individuals Biomass Phylum Phylum Mean Percent rank Mean Percent rank No. /m2 g/m2 PORIFERA 0.42 0.04 12 0.037 0.04 11 COELENTERATA 15.26 1.41 5 2-933 3.31 5 Hydrozoa 9.78 0.90 0.202 0.23 Anthozoa 5.48 0.51 2«731 3.08 Alcyonacea 0.12 0.01 0.045 0.05 Zoantharia 2.04 0.19 2.549 2.87 Unidentified 3192 0.31 0.138 0.16 PLATYHELMINTHES 0. 39 0.04 13 0.007 0.01 14 Turbellaria 0.39 0.04 0.007 0.01 NEMERT EA 4.88 0.45 8 0. 342 0.39 9 ASCHELMINTHES 1.64 0. 15 10 0.006 0.01 15 Nematoda 1.64 0.15 0.006 0.01 ANNEL IDA 160.16 14.78 . 9.102 10.27 3 POGONOPHORA 3.59 0.33 9 0.022 0.02 13 SIPUNCUE IDA 0.59 0.05 11 0.383 0.43 8 ECHIURA 0.18 0.02 14 0.411 0.46 7 PRIAPULIDA 0.01 * and 24/m". At four inshore and midshelf localities, den- N28 sity ranged from 25/m> to 75/m'. Biomass was gen- erally small, less than 0.5 g/m, but localities ranged from 0.5 and 11.5 g/m in nine localities. Coelenterata (figs. 11 and 12) were distributed broadly throughout the region. They were particu- larly widespread on the Continental Shelf and Slope. Densities over most of their range were low, less than 25/m*. Moderate densities (25/m> to were found in only a few small aress, and high den- sities (greater than 1,000/m*) were rare. Biomasses of coelenterates revealed a distribution pattern simi- lar to that of density (except for the moderate quan- tities (5 to 99 g/m?) in rather extensive areas off southern New England), and throughout most of their range were less than 5 g/m'. Hydrozoa (figs. 13 and 14) have a rather wide distribution in the Middle Atlantic Bight region. Except for part of southern New England, they were present in a broad band on the Continental Shelf extending from Cape Cod to Cape Hatteras. They were present in some of the northern bays, but were not found in central or southern bays. They were found in a few places on the Continental Slope. Den- sities over most of their range averaged between 1/m' and 49/m'. They were present in moderate to high densities (50/m* to 1,071/m>) in a few rela- tively small areas. Biomass was small (less than 0.5 over most of their range, but moderate to large quantities (0.5 to 47 g/m?) were present in in small areas, especially inshore and in the Cape Cod region and Chesapeake Bight. Alcyonaria [Alcyonacea] (figs. 15 and 16) were distributed in a narrow band in offshore waters along the Outer Continental Shelf, Slope, and part of the Continental Rise. The band extended from the Cape Cod region southward to within 100 km of Cape Hatteras. Densities at all localities were low (less than 26/m*) and were very low (less than over much of their range. Biomass was small to moderate (0.01 to 5 g/m?) over most of their range, but in two small areas south of Cape Cod, it was between 5 and 9 g/m. Zoantharia (figs. 17 and 18) were widely dis- tributed in a somewhat scattered pattern through- out the region. Their largest area of occurrence was in offshore Southern New England. Although they were taken in the bays, on the Continental Shelf, Slope, and Rise, they were most common on the Outer Continental Shelf. Throughout most of their range their densities were less than For a rather large area on the outer shelf of Southern N24 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES DENSITY Number per square meter 1 - 49 50 - 199 200 - 999 1,000 - 4,999 . 5,000 - 58,028 ALL TAXA FIGURE 7.-Geographic distribution of the density of all taxonomic groups combined for the Middle Atlantic Bight region. Density is expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N25 BIOMASS Grams per square meter 001 - 2499 2900 - 9299 10000 - 499.99 . 500,00-19,359.35 Yo ALL TAXA FIGURE 8.-Geographic distribution of the biomass of all taxonomic groups combined and expressed as damp weight per square meter of bottom area. N26 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES R % & (v) lg \ ~" :g wt! {x & E 00 .sp gna" "a ( G 6 f T3 p : % | {J : f} z yt //*/ Paull y Fal // 'a # / / / / [ [ l] J [f s \ / ¢ DENSITY \ ( ) C } Number per 4 E square meter ~ . \\ Tass J 1-24 ~ | { 25-75 \ \ \ 1 A {If \ : \ \ ; A ; ~ . N a A £ ¥ *% y*: | f 1 / 1.¢ 3 0 fe af* & 0 | al 1 | ..\| PORIFERA 1 FIGURE 9.-Geographic distribution of the density of Porifera, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N27 gr" sA f C" «bt .o up Bai! 09 l OS 8 , vy V / A F1 ¢ f & Rel y / © BIOMASS Grams per square meter U J h \ ( ) ( \ l \ | 1 -/ A L 601 - 949 s len 22/0 uP / 050-. 499 . 5.00 -11 45 1k PORIFERA FIGURE 10.-Geographic distribution of the biomass of Porifera, expressed as damp weight per square meter of bottom area. N28 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES DENSITY Number per square meter 1 - 24 25 - 99 100 - 999 . 1,000 - 2,292 o 61> o (x «\ COELENTERATA FIGURE 11.-Geographic distribution of the density of Coelenterata, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION BIOMASS Grams per square meter 001- 499 500- 99.99 l 100.00- 342.26 of/ r/ § a ..... COELENTERATA FIGURE 12.-Geographic distribution of the biomass of Coelenterata, expressed as damp weight per square meter of bottom area. N29 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES N30 o \ : & i' G g m." "# :> & y Cy ° 2 y V }( o i & 43?) DENSITY Number per square meter 1 - 49 50 - 199 I ~~~ o aP HYDROZOA FIGURE 13.-Geographic distribution of the density of Hydrozoa, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N31 BIOMASS Grams per square meter 0.01- 049 050- 4.99 I 5.00-46.86 HYDROZOA FiGurE 14.-Geographic distribution of the biomass of Hydrozoa, expressed as damp weight per square meter of bottom area. N32 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES DENSITY Number per square meter 1-9 10-26 o ,bD< 0 ALCYONARIA FIGURE 15.-Geographic distribution of the density of Alcyonaria, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N33 BIOMASS Grams per square meter 0.01 -0.49 0.50-4.99 . 500-8.57 \ c \ o 1 \ 1 ; L : bi 1 © fbb‘ I I I o a ALCYONARIA FIGURE 16.-Geographic distribution of the biomass of Alcyonaria, expressed as damp weight per square meter of bottom area. ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES N34 i_" | = meal _| CC } Z y "y. \ " ." C s\ . ~BOSTON y &. | : 4 % }(/ ' f f 66V $t e AF NEW YORK ad | ¢ DENSITY | (\ € < Number per s s square meter 1-24 25 -9%9 . 100-255 | \ I | i 3 af* s I I ZOANTHARIA FIGURE 17.-Geographic distribution of the density of Zoantharia, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N85 I «rt a I é bide Q)? (v) o sa. ' WF» wt o B 2" 7] % 7 &! 5 j BOSTON g #$ | Igs & 1" s TH) 4 I c 3 & /. aP BIOMASS Grams per square meter 0.01- 0.99 1.00 - 24.99 2500- 9999 . 100.00 - 342.26 o 43K)! p=-_ _._ L _._ ZOANTHARIA FIGURE 18.-Geographic distribution of the biomass of Zoantharia, expressed as damp weight per square meter of bottom area. N36 New England, their density was between 25/m> and 99/m'. They were present in only three small areas at densities greater than 100/m'. Biomass in about half their area of occurrence was less than 1 g/m, and between 1 and 25 g/m in the other half. A few relatively small areas, most of which were in coastal or inshore locations, had biomasses ranging from 25 to 342 g/m. Platyhelminthes (figs. 19 and 20) were distributed rather widely on the Continental Shelf throughout the region. For the most part they occurred in rather small patches. Densities were low (less than 25/m') at all locations except one. Biomass was small (less than 0.5 g/m) throughout their range, except at two localities. Nemertea (figs. 21 and 22) were very common and were distributed over a large part of the Middle Atlantic Bight region. Their density, however, was generally low, between and 24/m'. At only a few places in the bays and on the Continental Shelf south of Cape Cod did their density sverage between 25/m> and 235/m'. Nemertea were absent from most sampling stations in the bays and on the Continental Rise. Nemerteans accounted for a small proportion of the region's biomass. At most localities where they were found, their biomass was less than 1 g/m. Over an estimated 10 percent of their range, their biomass was between 1 to 25 g/m. At only two lo- calities was their biomass greater than 25 g/m. Nematoda (figs. 23 and 24) were found in a mod- erate-sized area of the region, somewhat scattered, but most common along the Outer Continental Shelf, Slope, and Continental Rise. Densities were gen- erally low, ranging from 1/m' to 24/m'. Moderate densities to were found in a few localities, mainly on the Continental Shelf south of Cape Cod. Biomass was very smail, less than 0.2 g/m' in most localities, and between 0.2 and 0.4 g/m in one area in the Chesapeake Bight subarea. A very large number of small nematodes, partic- ularly the larval stages, are believed to have passed through the sieving screen during sample processing. What proportion of the nematode kiomass that is represented by the large specimens retained on the screen, reported here, is unknown. Annelida (figs. 25 and 26) were ubiquitous throughout the entire Middle Atlantic Bight region. Densities were highest on the Continental Shelf. A particularly large area of moderately high density - (500/m> to 1,999/m>) was found on the shelf south of Massachusetts. Moderate densities prevailed in the New York Bight subarea, and low densities (less than in extensive areas in Chesapeake Bight. ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES Low densities, also, were characteristic of the Con- tinental Rise. Biomass reflected the same pattern as density. Over a very large part of the Continental Shelf, extending from Long Island, N.Y., southward to Cape Hatteras, the biomass of Annelida was be- tween 1 to 25 g/m". Off southern Massachusetts, a large expanse contained between 25 and 200 g/m. Low biomasses (less than 1 g/m*) were charac- teristic of the Continental Rise. Pogonophora (figs. 27 and 28) were present throughout the entire deepwater ares between Cape Cod and Cape Hatteras, primarily, on the Con- tinental Slope and Rise, plus several localities on the Outer Continental Shelf. They were present in rather low densities (to throughout most of their area of occurrence. Moderate densities (25/m' to 99/m%) were found in several areas along the Continental Slope. In only one locality, densities were high (100/m* to 335/m*). Biomass was small, less than 0.5 g/m, in all localities except two, where it ranged from 0.5 to 2.9 g/m. Sipuncula [=Sipunculida)] (figs. 29 and 30) were found over a wide geographic area, extending from the Cape Cod region southward to Cape Hatteras and were centered primarily on the Continental Shelf and Slope. Moderate numbers were found on the Continental Rise, but only limited numbers in the bays and sounds. In the northern part, they were found in shallow waters, whereas in the middle and southern sectors they were absent from the inner and middle shelf regions. Their density was less than 24/m* throughout most of their range, but in several localities in the northern shelf area it ranged from 25/m* to 99/m*. At only one location, a north- ern inshore area off Rhode Island, were they found in high density (100 and 311/m>). In roughly half their area of occurrence, biomass was less than 1 g/m; in somewhat less than half their area of occurrence, biomass ranged from 1 to 25 g/m"; in only two areas, the Continental Slope and Rise bio- mass was large (25 to 85 g/m*). Echiura (figs. 31 and 32) were sparsely dis- tributed in the region, and most were found on the Continental Rise. One small patch was found on the mid-Continental Shelf off Virginia and two small patches were found in inshore waters at the tip of Long Island, N.Y., and in Pamlico Sound, N.C. Den- sity ranged from 1/m> to and biomass ranged from 0.01 g/m" to 27 g/m. Priapulida (figs. 31 and 32) were found in only three places-two on the Continental Slope and one on the Continental Rise. Quantities were very small. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION DENSITY Number per square meter 1-24 200-237 t.. __ 8 | PLATYHELMINTHES FIGURE 19.-Geographic distribution of the density of Platyhelminthes, expressed as num- ber of individuals per square meter of bottom area. N37 N38 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES ( penn, mmm po. . . e «(If f i go of) 4 : o ' eas ; ® > x If \E\_/) QS‘ (x A_. . ~BOSTON.: !. © 9 £ . © ¢ aP 9 a> | tral g (y .B & « | 0 ~f gl p ) J/ /f /v// // // // / / / / [ [ ‘ o 6 P FA J «I BIOMASS | K) \ Grams per E square meter y y I'? 001-049 ©.50-:0.99 I 0.99-1.27 \ \ ) \\ \ \ \\ \\ \ % §. yf ) | P/} 1 4 o by? (s aJ : [.% KLOME I/ $4 af Figs PLATYHELMINTHES FigurE 20.-Geographic distribution of the biomass of Plathyhelminthes, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION lm __. DENSITY Number per square meter 1 - 24 25-99 . 100 - 235 o 6D o «D'- NEMERTEA FIGURE 21.-Geographic distribution of the density of Nemertea, expressed as number of individuals per square meter of bottom area. N39 N40 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES BOSTON \ somass |! Grams per square meter ©001- O99 1.00- 24.99 . 2500-52 82 p 43 o (x NEMERTEA FigurE 22.-Geographic distribution of the biomass of Nemertea, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION > £ Net een ern gs OP /- DENSITY Number per square meter 1 -24 25-99 . 100 - 627 o 43k o a NEMATODA FIGURE 23.-Geographic distribution of the density of Nematoda, expressed as number of individuals per square meter of bottom area. N41 N42 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES 6 "AHS iy x" L BIOMASS Grams per square meter (-_,\_/\_~f—fg & A> 0.20 -0.41 o “DIX o «bx NEMATODA FigUurE 24.-Geographic distribution of the biomass of Nematoda, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N43 y DENSITY Number per square meter 1.234 25-99 100-499 500 - 1999 . 2,000-34,786 o 430i o «bx ANNELIDA FIGURE 25.-Geographic distribution of the density of Annelida, expressed as number of individuals per square meter of bottom area. N44 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES BIOMASS Grams per square meter 001-099 1.00- 24.99 25.00 - 199.99 . 200.00 - 433.66 ANNELIDA Figure 26.-Geographic distribution of the biomass of Annelida, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION ath DENSITY Number per square meter 1-24 209-99 . 100-335 f ¥ I s POGONOPHORA 0 - < KILOMET FigurE 27.-Geographic distribution of the density of Pogonophora, expressed as number of individuals per square meter of bottom area. N45 N46 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES BIOMASS Grams per square meter Joot -o4d 0.50 -291 «& # 0 «bk ( POGONOPHORA FicUrE 28.-Geographic distribution of the biomass of Pogonophora, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION DENSITY Number per square meter 1 - 24 20 - 99 . 100 - 311 p t 0 a |_ SIPUNCULA FIGURE 29.-Geographic distribution of the density of Sipuncula, expressed as number of individuals per square meter of bottom area. ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES N48 iw-j—“7” L s r , 0 \ : At FA . & j Awa # D9 & € o o -$ & a As 1¢ f | / c C3 T3 ap BIOMASS Grams per square meter Qoo1- 093 1.00- 24.99 . 25.00-85.22 o C SIPUNCULA FigurE 30.-Geographic distribution of the biomass of Sipuncula, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION )\ ( m__ KL _ ___ _aAg ise ~> DENSITY Number per square meter sm mm Sie mee mo in cl, uni int [ ECHIURA PRIAPULIDA | ® FigUurE 31.-Geographic distribution of the density of Echiura and Priapulida (P), ex- pressed as number of individuals per square meter of bottom area. N49 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES N50 q” «(8 2 I. é 65° (3) I o - © the, E4) 0&0 DO h . BOSTON lb (so (190 % 5 ' f/ J > &, rJ/ PP ‘ //'// Pes / // ‘...: // | / / | I l g } > v:\ ps , ' BIOMASS [ s ‘,‘ Grams per \ square meter mol k" - $ : - 049 ¥ " 1 M I (_- @ 0.50 - 4.99 \ -P . 5.00 - 26.81 \ \\‘ f \\\ \ \ \\ \\\ (336 ~ (2; y | 3 (; 9 100 kiLometERg ** / f’ . ECHIURA g "ight. i PRIAPULIDA | ® FIGURE 32.-Geographic distribution of the biomass of Echiura and Priapulida (P), ex- pressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA Mollusca (figs. 33 and 34) were found at virtually all sampling stations in the Middle Atlantic Bight region; their geographical distribution was ex- ceptionally broad. Density was as high as 58,000/m*. Four density bands extend north to south, roughly parallel to the coast, throughout most of the region. The first band is in the bays and sounds and includes the inner Continental Shelf. This is a high-density (large areas having densities greater than 50/m>) band. The second band, parallel to the first, occupies the approximate middle of the Continental Shelf; this is a low-density (mostly less than 50/m*) band. The third band is along the Outer Continental Shelf and upper slope. This is a high density (mostly greater than band that broadens at the morthern end. The fourth band, along the Lower Continental Slope and Continental Rise, is a low- density (fewer than 50/m*) band. Biomass of mol- lusks is as great as 9,555 g/m". Exceptionally large areas of large biomass (greater than 100 g/m) occurred on the Continental Shelf, particularly be- tween Cape Cod and Delaware Bay. Moderate quan- tities (5 to 99 g/m) also prevailed in extensive areas in this region. In the Chesapeake Bight sub- area, the typical biomass of mollusks was less than 5 g/m, except in some inner shelf areas and along the shelf break. Polyplacophora (figs. 35 and 36) were distributed in small and rather widely separated patches, pri- marily on the Outer Continental Shelf, Slope, and Rise. They were found in only two localities in inshore waters. Density throughout most of their area of occurrence was less than 24/m>', and biomass typically was smaller than 0.5 g/m*. Gastropoda (figs. 37 and 38) were distributed over extensive areas extending from the northern to the southern boundaries of the region and from inshore waters to the outermost areas sampled. Out- side the bays and sounds, their distribution gen- erally formed bands parallel to the coastline. A mod- erately high density to 99/m*) band was present along the coast. Just seaward of this high- density band was a low-density (less than 10/m') band. In the central and outer parts of the Conti- nental Shelf, gastropods were absent, except in the area south of Rhode Island and Massachusetts where a density of 10/m> to was found. Along the Upper Continental Slope, the density was moderately high, and low-density bands were on either side. Biomass was small to moderate (0.01 to 5/m*) over most areas of gastropod distribu- tion. Intermediate (5 to 25 g/m*) patches of bio- masses were distributed primarily along the inner OF THE MIDDLE ATLANTIC BIGHT REGION N51 shelf areas and in bays and sounds, but a few patches were found in the midshelf regions south of Cape Cod and south of Long Island. Large bio- masses (25 to 394 g/m?) were restricted almost ex- clusively to bays and sounds, except for one small area in midshelf depths south of Nantucket Shoals. Bivalvia (figs. 839 and 40) were ubiquitous throughout the Middle Atlantic Bight region .Their pattern of density formed bands more or less parallel to the coastline. A narrow band of moderate density (50 to 500/m*) was found along the coast. A some- what broader band of low density (less than 25/m>) ran through the central part of the shelf. Another band of moderate density, very broad in the South- ern New England area and narrower in the southern section, extended the entire length of the region. Biomass patterns were essentially similar to those of density. Two bands of small biomass (0.01 to 5 g/m*) were found, one offshore beginning on the outer part of the Continental Shelf and extending to the deepest depths sampled; the other occupied the midshelf regions east of Long Island and below New York City. Two bands of moderate biomasses (5 to 50 g/m?) were situated on the Inner and Outer Con- tinental Shelf. Patches of large biomasses (50 to 19,300 were found in bays and sounds throughout the entire region and on the middle to outer shelf region of Southern New England and New York Bight. Large offshore biomasses in the more southerly regions were confined to the outer shelf. Scaphopoda (figs. 41 and 42) were distributed in a narrow (25 to 50 km) band along the Outer Con- tinental Shelf and Slope extending the entire length of the Middle Atlantic Bight region. Density was low (less than throughout this band, except at four localized areas where it ranged from 25/m' to 77/m'. Biomass was small (less than 0.5 g/m>) throughout most of this band, and reached a maxi- mum of only 2.46 g/m. Cephalopoda (figs. 35 and 36) were represented entirely by eggs. They occurred in moderately small quantities at only two localities on the Outer Con- tinental Shelf off southern Massachusetts. Arthropoda (figs. 43 and 44) were nearly ubiqui- tous throughout the entire region. They were one of the most comman taxonomic groups found; maxi- mum density was 19,171/m'. High densities (greater than were prevalent in large areas of the Continental Shelf in the Southern New England subarea and in the northern half of the New York Bight. Moderately high densities (200/m' to 1,999/m*) were found over extensive areas in N52 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES DENSITY Number per square meter 1-49 50 - 199 200 - 1999 . 2000 - 58,028 U 430‘ o a MOLLUSCA FIGURE 33.-Geographic distribution of the density of Mollusca, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N53 BIOMASS Grams per square meter 001 - 499 500 - 9999 . 100.00-9,55504 o 4)“ 0 10K MOLLUSCA FIGURE 34.-Geographic distribution of the biomass of Mollusca, expressed as damp weight per square meter of bottom area. N54 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES DENSITY Number per square meter a i ee, . ~> we 1-24 #7 -~ N- 29=TB mem _- 12% Vsl |G (2 I CEPHALOPODA | FIGURE 35.-Geographic distribution of the density of Cephalopoda (C) and Polyplaco- phora, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N55 qt‘ffi'fA' m A Al f j i & f § QxxTWLb-Q’ s BOSTON BIOMASS Grams per square meter 0.01- 0.49 | [_ |« POLYPLAGOPHORA Figur® 36.-Geographic distribution of the biomass of Cephalopoda (C) and Polyplaco- phora, expressed as damp weight per square meter of bottom area. ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES N56 DENSITY Number per square meter 1-9 10-99 100-999 . 1000- 5,525 0 60x 0 a GASTROPODA FIGURE 37.-Geographic distribution of the density of Gastropoda, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N57 BIOMASS Grams per square meter 0.01 - 4.99 5.00 -24.99 . 25.00-393.67 GASTROPODA FIGURE 38.-Geographic distribution of the biomass of Gastropoda, expressed as damp weight per square meter of bottom area. N58 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES \©* BOSTON DENSITY Number per square meter 1 - 25 26 - 49 50 - 499 500 - 4,999 . 5,000 - 58,028 ©.100 KILOME TEI o a BIVALVIA FIGURE 39.-Geographic distribution of the density of Bivalvia, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF + / BOSTON .c. 100 KILOM BIOMASS Grams per square meter oo1 - 499 500 - 4999 . 50.00- 19,359.35 BIVALVIA THE MIDDLE ATLANTIC BIGHT REGION FigurE 40.-Geographic distribution of the biomass of Bivalvia, expressed as damp weight per square meter of bottom area. N59 N6O ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES Yflq] y fis é org. f > C3 (v) : § f ( A x> ¢ p Boston _ K ¢ Cr .sB g £2: e ie f/ j a! 31. & s DENSITY Number per square meter 1-24 aa rere . KILOMET SCAPHOPODA FIGURE 41.-Geographic distribution of the density of Scaphopoda, expressed as number of individuals per square meter of bottom area. N6L INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION MACROBENTHIC TE“; A enas *- esses lvd eit tim D NE) & P Mau y ape Aki ~ oa & ak . ... CBOSTON; 9 & ; yoo? 66: ad BIOMASS Grams per square meter 0.01 - 0.49 0.50 - 2.46 o 430l o «bx SCAPHOPODA FIGURE 42.-Geographic distribution of the biomass of Scaphopoda, expressed as damp weight per square meter of bottom area. N62 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES DENSITY Number per square meter 1 - 49 50 - 199 200 - 1,999 I 2000 - 19.171 o 43°l o a ARTHROPODA FigurE 43.-Geographic distribution of the density of Arthropoda, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION BIOMASS Grams per square meter Oo1 - O99 1.00 - 24.99 2500 - 199.99 I 200.00 - 1,139.76 / ARTHROPODA FIGURE 44.-Geographic distribution of the biomass of Arthropoda, expressed as damp weight per square meter of bottom area. N63 N64 inshore waters and on the Continental Shelf through- out the region. Low densities (less than prevailed in the offshore deepwaters. Biomass had a somewhat similar pattern of distribution. Large (greater than 200/m?) and moderately large (25 to 199 g/m) biomasses were most common on the Con- tinental Shelf in Southern New England. Moderate quantities (1 to 25 g/m') were found in extensive areas of the Continental Shelf. Small quantities (less than 1 g/m*) were prevalent in the Chesapeake Bight subarea and in offshore deepwater. Pyenogonida, Arachnida, Ostracoda, Nebaliacea, and Copepoda (fig. 45) were found in only a few scattered localities. Densities varied in magnitude from one group to another, but generally they were low, and the biomass of all groups was very small. Cirripedia (figs. 46 and 47) were present in only a few localities, primarily on the Continental Shelf. Most were found in the area from New York north- ward to Cape Cod, also the area of its highest den- sity (500 to 7,932/m*). Biomass was distributed in a similar pattern and reached quantities ranging from 500 to 1,104 g/m at localities of highest den- sity. Cumacea (figs. 48 and 49) were widely distributed throughout the region, particularly on the Conti- nental Shelf, from shallow inshore waters to offshore deepwaters, and from Cape Cod to Cape Hatteras. High densities (greater than 500/m*) and mod- erately high densities (100/m> to 499/m®) were com- mon on the central Continental Shelf off Southern New England, and along the outer margin of the Continental Shelf in the Chesapeake Bight subarea. Low densities (less than 25/m*) prevailed for most of their area of occurrence on the Continental Shelf and in all deepwater areas. Biomass was small (less than 0.5 g/m?), except for widely scattered patches of limited size. Tanaidacea (figs. 50 and 51) were found only in deepwater. They were found in small and widely sep- arated areas on the Continental Slope and Rise ranging from offshore Cape Code to the offshore Chesapeake Bay region. In all localities their density was low, less than 6/m?, and their biomass was small, less than 0.05 g/m. Isopoda (figs. 52 and 538) were widely dispersed over the Continental Shelf throughout the region at densities ranging from 1/m" to 24/m*. Moderate- size areas, more or less equally distributed over the Continental Shelf, contained populations between and 199/m'. High densities (200/m' to 1,053/m*) were restricted to small areas, chiefly the bays and the Inner Continental Shelf. Biomass ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES throughout most of their area of occurrence was less than 0.5 g/m*. Some moderately large areas, rather evenly scattered throughout the region, contained bio- masses between 0.5 and 5.0 g/m'. In a few small areas, along the middle and inner shelf between New Jersey and Virginia, they were present in relatively large quantities, 5 to 12.6 g/m. Amphipoda (figs. 54 and 55) were ubiquitous in the Middle Atlantic Bight region where densities ranged from 10/m* to more than 19,000/m*. Lowest densities were most closely associated with the deep water below the shelf break and in patches along the coastline. Moderate densities (50/m* to 500/m*) predominated on the Continental Shelf below the eastern tip of Long Island. Higher densities (500/m> to were distributed in relatively large areas off Southern New England, somewhat smaller areas in the New York Bight region, and the smallest areas in the more southerly reaches of the study area. Highest densities (5,000/m' to 19,000/m>) were found only in comparatively small patches in the Southern New England region. Biomass ranged from 0.01 to 175 g/m. Largest biomasses (25 to 175 g/m?) were, like density, most prevalent in the northern sectors of the study area and in a few dis- crete patches in the south. Intermediate biomasses (1-25 g/m*) were present over large parts of the Southern New England and New York Bight Con- tinental Shelves, and in smaller areas farther south. Generally, the inshore and offshore areas contained the smallest (0.01 to 1 g/m?) biomasses. Mysidacea (figs. 56 and 57) were present in scat- tered localities from Cape Cod to Cape Hatteras. All samples except one were from the Continental Shelf, primarily in coastal areas and the Inner Continental Shelf. Densities were low (less than 25/m?) in about half their area of occurrence and moderate (25/m* in the remaining half. Biomass of mysids was small (less than 1.4 g/m) at all localities. Decapoda (figs. 58 and 59) were found over a large part of the Middle Atlantic Bight. They were broadly distributed on the Continental Shelf, extend- ing from Cape Cod to Cape Hatteras. Densities over most of this expanse were low (less than 25/m?) and moderate (25/m' to 99/m>) to high to 395/m>) in rather small seattered patches in all see- tions. Biomass was distributed somewhat differently in that most of the largest quantities were on the Inner and Middle Continental Shelf and smaller quantities were on the Outer Continental Shelf. Bryozoa (figs. 60 and 61) were distributed in moderate-sized patches in the study area. Densities, for the most part, were rather low (1/m> to 24/m?); MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE CW |", Ax.? Sll‘D‘O p £ B ® § 4 (1 | <)\l. QC; oO // - Q3\ 0 ¥ I/C I | ) $ 7' n J/ | (\ | I Ad, __ ¥: | \} " 5 \\\J as DENSITY | a A40 g One or more per square meter H1 o Ss \\\ { p Is N s. NEBALIACEA | * ARACHNIDA OSTRACODA | o COPEPODA | © PYCNOGONIDA | ® FiGgurE 45.-Geographic distribution of the density of Arachnida (A), Copepoda (C), Nebaliacea (N), Ostracoda (O), and Pycenogonida (P), expressed as number of in- dividuals per square meter of bottom area. ATLANTIC BIGHT REGION N65 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES N66 ikii_"'_"kd ' i F ¥ v/(lf e> i - & (J) I o aas g 02°73» 5 ‘ 1:4) Os” o m | \ ®) [%. ~. (Boston # $ .$ g Pee : * 3 | $ f | & ¢! { "3 ) 7. } (2 | # //—/ / // // / I / / / | I l o | ## wZ A | / f DENSITY ( ps ) (\ { Number per ] square meter w \ J 1 - 49 N \ I $ 50 - 499 \ - 500 - 7.932 \ \ I \ N \ \ \ \\ N \ \ \ I \ 1 1% is. G 0 f i 100 KlLOMETER { ll «be | IRRIPEDIA FIGURE 46.-Geographic distribution of the density of Cirripedia, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION BOSTON: y { ) \ Secs? M we neg Samm target. ~> ,7 se ~ NAe me" §, 22 en nop, 12. ©1600 kiLometER$ ** l e 2g W.! e DO s | p o - & v $Y } & /( < % $ {7 4 C / / r_/ -/ o aP BIOMASS Grams per square meter 0.01 - 0.99 100 - 24.99 100.00- 499.99 . 500.00-1,103.96 Yo CIRRIPEDIA FIGURE 47.-Geographic distribution of the biomass of Cirripedia, expressed as damp weight per square meter of bottom area. N67 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES N68 - 1 - mmm mmm Pa «(If L é 058 (v1 i o } 62x" >* { s ' E 0 | A_. ./ ~BOSTON 5 | : Are y- *V | /. \& aP | DENSITY Number per square meter T - 24 29 =99 o “JD‘ / | R ( Al CUMACEA o ~©.100 KiLometTERs fat an, FIGURE 48.-Geographic distribution of the density of Cumacea, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION I Pit y ©é a D90 A\ -. (BOSTON: 1 - y (ng ad Biomass _ || Grams per square meter 0.01-0.49 0.50-4.99 . 500-502 43m o - kiLomeTERs! g CUMACEA LX 4 FIGURE 49.-Geographic distribution of the biomass of Cumacea, expressed as damp weight per square meter of bottom area. N69 SHELF AND SLOPE OF THE UNITED STATES N7O ATLANTIC CONTINENTAL (o amine o. nai ae mae a "_ a" C ; é O _ f f f {rf o b E, $.." is A. .. ~BOSTON: g § {& | j at v, ho / § > al 7 3 / / (J F //V/ / // // e | / / / [ 1 | $ 37 a *% e 4 > {009 DENSITY k ; ( ) (\ { Number per } square meter m | b/ 1-6 Bul 2 Sitt: cud ane ~ 1 I £ I \ a6 1% \ \ 1 \\ A : \ \ j \ % * XA % 1 & Yie 11 ¢ yen #; £! 1% (G 100 KILOMETE ( $ LG TANAIDACEA FiGurE 50.-Geographic distribution of the density of Tanaidacea, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION t" C GND P Q: (7) $ o s 3 (x g ¢ . 3B § a> a. 'A C | §;/ o! P iss Qk‘: ) f / f. ': a K/ : ‘ //V/ 205 /// . - /(, /* I ) " / [ ( 1 # *--> I 1 J T BIOMASS | (\ 3 Grams per to (“I : square meter \\ / 10.01 - 0.05 ) 4 I ¢ | \ \ \ « A {If \ \ 1 \ ~ \ \ \ X \\ \ \ \ l J=} to | C. {.; 1 o co - SC C f (f as 26) | TANAIDACEA FIGURE 51.-Geographic distribution of the biomass of Tanaidacea, expressed as damp weight per square meter of bottom area. NTL N72 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES xp o \ 1. _ A+ é o C&L 0/1 f (0) firm}. pt *~. % £ i T Z & (] h BOSTON on. f %. "V / & Syst. Se ( % N / | | 1p DENSITY 1 | Number per square meter t =:24 25> 199 | . 200 - wos 6b '4\%°,-.- :. f ISOPODA FIGURE 52.-Geographic distribution of the density of Isopoda, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION x g O BOSTON BIOMASS Grams per square meter : ] ao1- 049 . 500 - 1262 9850 < 499 I pais ersten ul 43°? T co . T f as 2 a ( , FiguUurE 53.-Geographic distribution of the biomass of Isopoda, expressed as damp weight per square meter of bottom area. NT a o N74 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES 3 «(L a a 7 G (w) _ f on 1. . . $2 ;.'i.@75-1 : 8 ¥ «E; 0’s- ® *% .. BOSTON. ? g .f f & . sg | DENSITY Number per square meter 1-49 50 - 499 500 - 999 ....... 1,000 - 4,999 . 5,000 - 19,068 ~ uud .. UU KILOMETERE a " , AMPHIPODA FIGURE 54.-Geographic distribution of the density of Amphipoda, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION s KILOMe TERS 1% L3. g # 2.1, § 7"4 . BP qee a _) "c gf> is f © f E“ & ! 1 BOSTON: 9 | & t ad BIOMASS Grams per square meter 001 - 092 1.00- 24.99 . 2500-17491|| o / HHAIT 4—9 [ A AMPHIPODA FIGURE 55.-Geographic distribution of the biomass of Amphipoda, expressed as damp weight per square meter of bottom area. N75 N76 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES G ) /o wear 3c? mu ece DENSITY Number per square meter Ae. cn whe ~> 1-24 /7 w" C_ o 60x o (. [T_ lee MYSIDACEA FicurE 56.-Geographic distribution of the density of Mysidacea, expressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION kasey yAt (s\ _- BOSTON: o *! a." BIOMASS Grams per square meter I \ I {a: p i = F | | WYSlDACEA 4 oo01 -049 0.50 - 1.41 € 43° if FIGURE 57.-Geographic distribution of the biomass of Mysidacea, expressed as damp weight per square meter of bottom area. N77 N78 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES «(i tel i be O) : 0° r : @t" uk "A \_ _- BOSTON 2° ¢ 4 : y ¥: | ._ / t /( “‘ I) Gel ad DENSITY Number per square meter [J += EEE] 29-99 I 100-395 o “Du o a DECAPODA FiGurE 58.-Geographic distribution of the density of Decapoda, expressed as number of individuals per square meter of bottom area. NT9 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION r‘_' T ants r C V y~"e ' o 7 ro i > &' w) ' $ C L Q. to £ 05 | BOSTON § .$ ; q V , P . | /( 0: & % / - .$ BIOMASS Grams per square meter 001 - 049 0.50 - 4.99 500 - 24.99 . 25.00 -64 82 43> o [x. DECAPODA FigurE 59.-Geographic distribution of the biomass of Decapoda, expressed as damp weight per square meter of bottom area. N80 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES G ) \ ~ __ ~ _- DENSITY Number per square meter ai mie tua =, 1-24 29-99 100-499 ! BRYOZOA | BRACHIOPODA | » o . ill. ~aoomLomeTtens *** | * <." FiGuUrE 60.-Geographic distribution of the density of Bryozoa and Brachiopoda (B), ex- pressed as number of individuals per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION higher densities occupied smaller, discrete patches on the periphery. Biomass, similarly, was mod- erately small (0.01 to 1.0 g/m?) over most of their range, and larger biomass (1 to 52 g/m*) was found only in small isolated patches. Brachiopoda (figs. 60 and 61) were distributed only in a relatively small area on the Outer Con- tinental Shelf northeast of Cape Hatteras and south- east of Norfolk, Va. Densities ranged from 1/m* to 99/m> and biomass was less than 1 g/m*. Echinodermata (figs. 62 and 63) were widely dis- tributed throughout the region. High densities (greater than 200/m*) and moderately high den- sities (25/m" to were found on the Outer Continental Shelf in Southern New England, along the inner shelf in New York Bight, and on the cen- tral shelf in Chesapeake Bight. Echinoderms were present in low densities (less than 25/m') in most of the bays and sounds, over substantial parts of the shelf, and in the deepwater beyond the Continental Shelf. The biomass distribution was somewhat simi- lar to that of density, but considerably more irreg- ular. Large (5 and 99 and very large (100 and 855 g/m?) biomasses were common over large expanses of the Continental Shelf and in several places on the slope and rise. Holothuroidea (figs. 64 and 65) were distributed in a broad irregular area centered along the Outer Continental Shelf extending from Cape Code to Chesapeake Bay. Densities over most of this area were relatively low (less than 25/m*®). In a few areas, particularly off southern Massachusetts, the density ranged from 25/m> to 201/m*. Biomass was small to moderately small (0.01 to 5 g/m) over most of their range except in two fairly extensive areas on the Outer Continental Shelf, one south of Cade Cod and the other east of Norfolk, Va., where biomasses were between 5 and 664 g/m. Echinoidea (figs. 66 and 67) were found over much of the Continental Shelf throughout the entire region. They were absent in the bays and sounds (with one exception in outer Long Island Sound) and were present on the Continental Slope and Rise only in this northern region. Densities in a little over half their area of occurrence were less than 25/m'. Along the inner shelf in the northern and central sec- tions and in midshelf in the Chesapeake Bight re- gion, they were present in densities ranging from 25/m to 500/m?, and, in a few limited areas in the New York-Delaware sector, densities were between 500/m" and 2,083/m*. Echinoids constituted a rather sustantial biomass. In most of their range, their biomass averaged between 0.01 and 25 g/m. In N81 roughly 10 percent of their range, biomass averaged between 25 and 100 g/m. In roughly 5 percent of their area of occupancy, including a large area on the Outer Continental Shelf off Cape Cod, their bio- mass ranged from 100 to 855 g/m*'. Ophiuroidea (figs. 68 and 69) were distributed along the entire length of the Middle Atlantic Bight region, primarily in deep water (100 m or greater), but extending inshore in Southern New England and a few localities farther south. Densities were moderately low (less than 25/m?) over most of their range. Moderate and high to 1,018/m*) con- centrations were found in a rather broad band along the Outer Continental Shelf between offshore New York and Cape Cod. The pattern of biomass was somewhat different from that of density. Moderately small biomass (less than 1 g/m*) was found over roughly one half of its range, and moderate (1 to 25 g/m) to high (25 to 77 g/m*) over extensive patches throughout their area of occupancy. Asteroidea (figs. 70 and 71) were found over a rather extensive area between Cape Cod and Cape Hatteras. They were more common and their density was highest in the New England region. In most localities, their density ranged from 1/m' to o /m. In New England Bight (and at one locality in New York Bight), their density in a rather large area ranged from 10/m' to 48/m*. In the Chesapeake Bight, they were found primarily in deepwater areas extending from the Outer Shelf to the Continental Rise. Biomass of starfish over most of their range averaged between 5 and 50 g/m". At a few places in Southern New England-New York Bight, their biomass was between 50 and 210 g/m. In the Chesa- peake Bight, asteroids were found mainly on the Continental Slope and Rise and constituted a small biomass, commonly less than 0.5 g/m. Hemichordata (figs. 72 and 73) were found at only four localities, three were on the Outer Con- tinental Shelf and Slope south of Rhode Island and one along the coast at Cape May, N.J. Quantities at all localities were very small. Ascidiacea (figs. 72 and 73) were distributed in rather patchy areas over a large part of the Middle Atlantic Bight region. They were common in the bays and sounds in the northern section and in Chesapeake Bay. In the Southern New England sub- area, their density was low (less than 25/m*) to high (500/m> to 2,640/m*) on the Shelf, and on the slope and rise. In New York Bight, their density was commonly lower than 100/m'. In Chesapeake Bight, their density was generally low on the Con- tinental Shelf, but ranged from 100/m* to in N82 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES \ ) ~ OEL, 5h ev in mee, BIOMASS Grams per square meter hee L ea nan e i. 001 - 09%9 100-24.99 . 2500-5200 tno < " / || BRYOZOA { BRACHIOPODA | ® ILOMETE FIGURE 61.-Geographic distribution of the biomass of Bryozoa and Brachiopoda (B), ex- pressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION DENSITY Number per square meter 1-24 25 - 199 - 200 - 2,085 / ( _ECHINODERMATA FIGURE 62.-Geographic distribution of the density of Echinodermata, expressed as num- ber of individuals per square meter of bottom area. N83 N84 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES BIOMASS Grams per square meter 0.01 - 499 5.00 - 9999 -100AOO - 854.82 o 61> o 10k ( _ECHINODERMATA FIGURE 63.-Geographic distribution of the biomass of Echinodermata, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N85 DENSITY Number per square meter 1 24 25-99 . 100 - 201 o ,b& o «bx ~ HOLOTHUROIDEA FIGURE 64.-Geographic distribution of the density of Holothuroidea, expressed as number of individuals per square meter of bottom area. N86 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES Yo \ : & _. / M x2 x" p & § & 9 _G & a* Ir/ & % l) P q3%\ ) / 452? BIOMASS Grams per square meter | 001-4.99 5.00-49.99 . 50.00-664.20 0 43k I . $4 1s; [ fos af _HOLOTHUROIDEA FIGURE 65.-Geographic distribution of the biomass of Holothuroidea, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION DENSITY . 500 - 2,083 Number per square meter 1 - 24 25 - 99 100 - 499 \ 1 i [C I 1 o 43h o Als ECHINOIDEA FigurE 66.-Geographic distribution of the density of Echinoidea, expressed as number of individuals per square meter of bottom area. N87 N88 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES BIOMASS Grams per square meter 001- 24.99 2800 - 9999 . 100.00 - 854.82 ECHINOIDEA FIGURE 67.-Geographic distribution of the biomass of Echinoidea, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION H uas me {If lir é Q3? <3) rig *~. (BOSTON § # & DENSITY Number per square meter 1-24 25-99 100-499 I 500 - 1,018 OPHIUROIDEA FIGURE 68.-Geographic distribution of the density of Ophiuroidea, expressed as number of individuals per square meter of bottom area. N89 N9O ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES al 2g a Ly T., K.\'*-\. 7 BOSTON y BIOMASS Grams per square meter 001- 099 100-2499 . 2500-7662 OPHIUROIDEA FIGURE 69.-Geographic distribution of the biomass of Ophiuroidea, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION DENSITY het Asx, Number per square meter ~> C 1-9 10-24 . 25-48 o 6D G ab f ASTEROIDEA FIGURE 70.-Geographic distribution of the density of Asteroidea, expressed as number of individuals per square meter of bottom area. NQ1L N92 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES BIOMASS Grams per square meter 001 - 0.49 050 - 4.99 5.00 - 49.99 .50.00—210.59 ASTEROIDEA FIGURE 71.-Geographic distribution of the biomass of Asteroidea, expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N93 DENSITY Number per square meter 1-24 $9 100-499 I 500-2640 ¢ ASCIDIACEA HEMICHORDATA | ® FIGURE 72.-Geographic distribution of the density of Ascidiacea and Hemichordata (H), expressed as number of individuals per square meter of bottom area. N94 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES 6 . / ning 9 € OS O 00 s / S f % $ 0 4D?) BIOMASS Grams per square meter 001- 499 5.00- 49.99 . 50.00 -528.08 / ASCIDIACEA HEMICHORDATA | ® FIGURE 73.-Geographic distribution of the biomass of Ascidiacea and Hemichordata (H), expressed as damp weight per square meter of bottom area. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N95 Chesapeake Bay. The pattern of biomass was similar to that for density. Biomass in most areas was less than 5 g/m. In substantial areas in Southern New England, and in a few small areas farther south, the biomass averaged between 5 and 528 g/m. SELECTED GENERA AND SPECIES This section deals with the geographic distribu- tion of 24 selected genera and species of macro- benthic invertebrates. These particular forms were selected because of their common occurrence and a few were selected because of their distinctive dis- tribution. See figures 74-79. The species and genera illustrated, listed by phylum, are as follows: PHYLUM ANNELIDA Sternaspis scutata (Renier) (fig. 74A), a mod- erately small (1 cm), stout, burrowing polychaete of the family Sternaspidae. It commonly inhabits silty sediments. Scalibregma inflatum (Rathke) (fig. 74B), a me- dium-size (1-5 ecm) polychaete of the family Scali- bregmidae. This species, which commonly is found in silty sand, is an important food of demersal fish. Hyalinoecia tubicol« (Miiller) (fig. 74C), a large (10-25 ecm), tube-dwelling polychaete of the family Onuphidae. This is an active, epibenthic species that is characteristic of deep water. PHYLUM POGONOPHORA Siboglinum ekmani (Jagerston) (fig. T4D) , a small (5 em), slender pogonophoran of the family Sibo- glinidae. This is a tube-dwelling species charac- teristic of a deepwater environment. PHYLUM MOLLUSCA Arctica islandica (Linnaeus) (fig. 754), a rather large (8-15 cm), bivalve of the family Arcticidae. This is a slow-growing Continental Shelf species that is very abundant in some localities. It usually inhabits silty sand sediments. Cerastoderma pinnulatum (Conrad) (fig. T5B), a moderately small (1 cm), bivalve of the family Cardiidae. This small cockle has been taken in a wide variety of bottom sediments. Thyasira spp. (fig. 75C), represented in our sam- ples by five species of small (less than 1 em), bivalves of the family Thyasiridae. The species represented are: ferruginosa, flexuosa, ovate, pygmaea, and trisinuata. These bivalves are most commonly found in offshore waters and in fine-grained bottom sedi- ments. Cyclocardia borealis (Conrad) (fig. T5D), a me- dium-size (38-5 em), bivalve of the family Carditidae. Although it is more common in boreal waters, our samples showed it had a broad distribution in the Middle Atlantic Bight region. Lucinoma blakeana (Stimpson) (fig. 76A), a moderately large (5-7 cm), bivalve of the family Lucinidae. This thin-shelled species is most common in the Outer Continental Shelf waters. Emsis directus (Conrad) (fig. 76B), a large (10-17 em), bivalve of the family Solenidae. This is a very active, sand-dwelling species that inhabits shallow inshore waters as well as the Offshore Con- tinental Shelf. Polinices spp. (fig. 76C) , represented in our sam- ples by two species, P. duplicatus and P. immacu- latus. These species of carnivorous gastropods, family Naticidae, are typically found on sandy sedi- ments. Alvania spp. (fig. 76D), represented in our sam- ples by at least two species, A. brychia and A. carinata. These small (less than 5 mm) gastropods, family Rissoidae, are usually associated with silt- clay bottom sediments. PHYLUM ARTHROPODA Ampelisca spp. (fig. 77A), this genus of gammari- dean amphipods is represented in our samples by six species: abdita, aequicornis, agassizi, macro- cephala, vadorum, and verrilli. They are medium- size (4-7 mm), to moderately large (20 mm), tube- dwelling species. This is a common genus and repre- sentatives are distributed in inshore and offshore waters; very abundant in some localities. Leptocheirus pinguis (Stimpson) (fig. TTB), a moderately large (10-17 mm), gammaridean amphi- pod, family Aoridae, that is typical in Continental Shelf sand and silty-sand habitats. This species is a very important food of demersal fish. Phozxzocephalus holbolli (Kroyer) (fig. 77C), a moderately small (5-7 mm), member of the family Phoxocephalidae. This species characteristically in- habits bottom sediments composed of fine sand. Trichophozxus epistomus (Shoemaker) (fig. TTD), a medium-size (6-8 mm), burrowing amphipod of the family Phoxocephalidae. It is a widely distrib- uted species that inhabits sand and silty-sand sedi- ments. Cirolana spp. (fig. 78A), a medium-size (1-2 em), member of the Isopoda, family Cirolanidae. It is represented chiefly by C. polite (Stimpson), but at least one additional species is included. This is a N96 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES {$95 ° $ £ % « | $ 8 16 «6 +P 100 KiLOMETERS / Scalibregma inflatum .$ € & 4 3 & ¥: _-% //. $ Fo 16 < ie G J f ‘I. 0 wommuzags‘ / - fb / icola i>. 3% LIE/a lincecia tubico | FIGURE 74.-Geographic distribution (indicated by dots) of three selected species of Annelida (A-C) and one Pogonophora (D). MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N97 [T 19g “3257‘s 8 8 BOSTON _ " § 4 $ «Si Y ‘ | \| 16 < o 100 kicomeTeRs . |« / f | § Cerastoderma pinnulatum |g _-_, | Gerastoderma pinnulatumn ||| 4 < ed a $ 4B C *e \ ie A; 5 a + ( c 0 100 llLOfiRS. - ; m»! | Thyasira spp. p T - ~! Cyclocardia borealis # | EZ m 5 =z FIGURE 75.-Geographic distribution (indicated by dots) of selected bivalves, phylum Mollusca. N98 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES *." € no & $ « # < # # o 100 kirometens / 4. ¢ *! Lucinoma blakeana «€ .or * H 8" 8 I 1 &, & $ $ «(a 8. | 6 ( 16 €, € [ I ¥! | Polinices spp. FIGURE 76.-Geographic distribution (indicated by dots) of selected bivalves (A, B) and gastropods (C, D), phylum Mollusca. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N99 ¥T 's » ) «¥ f 5 $ Peas.? A L & gi « "* .|. .o.>, £ e 2° *.* * / e _*® o e a F ® @ ___ # / e" / 7 ® / f 1/ { ¢ a # i / ‘GF : h \ ( a6 auc -z _a « a¢ i ¥ 9 , 0 100 KILOMETER a / 0 100 KILOMETERS ore Pho ocephalus holbolli p T » 2 “v | Trighophoxus epistomus FIGURE 77.-Geographic distribution (indicated by dots) of selected amphipods, phylum Arthropoda. N100 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES ~-»- & o o* 7 » re on t te ad Buras a & fu» f € # £ 100 kicoweters - p: & 7 Crangon septemspinosa 100 kicometers Fo & [ | + } ig ld A [f < e ¢ ; 1 ‘\ i bf } ¥ I \\\ u ig } { \ { # | 16 < « \ \\ . i Ca a aP aP c Pagurus spp. FIGURE 78.-Geographic distribution (indicated by dots) of a selected isopod (A) and decapods (B, C, D), phylum Arthropoda. MACROBENTHIC INVERTEBRATE FAUNA common and widely distributed genus in the Middle Atlantic Bight region. Crangon setemspinosa (Say) (fig. T8B), a mod- erately small (5-8 em), caridean shrimp, order Decapoda. Typically, it inhabits sandy sediments, and is distributed throughout the region in both inshore waters and much of the Continental Shelf. Pagurus spp. (fig. 78C), medium-size (5-10 ecm), members of the order Decapoda, family Paguridae. They are represented in our samples by three species: P. acadianus, P. arcuatus, and P. pubescens. The most common and broadly distributed species is acadianus. Cancer spp. (fig. T8D), a rather large (5-15 ecm), heavy-shelled brachyuran crab, order Decapoda, family Cancridae. This genus was represented by two species: C. borealis and C. irroratus. Both species inhabit a variety of bottom sediments and are found throughout the Middle Atlantic Bight region. PHYLUM ECHINODERMATA Echinarachnius parma (Lamarck) (fig. 794), a moderately large (5-8 ecm), member of the class Echinoidea, family Scutellidae. This is a very com- mon species and is characteristic of sandy bottom sediments. Echinocardium cordatum (Pennant) (fig. T79B), a rather large (5-10 cm), member of the class Echinoidea, family Spatangidae. This is a burrowing species that usually inhabits sand sediments in mod- erately shallow water. It is found only in the south- ern part of the region. Astropecten spp. (fig. 79C), moderately small (8-12 ecm), members of the subclass Asteroidea, family Astropectinidae. This genus is represented by two species: A. americanus (Verrill), and A. articu- latus (Say). These are carnivorous, burrowing spe- cies that are common in silty-sand bottom sediments on the Outer Continental Shelf. OF THE MIDDLE ATLANTIC BIGHT REGION N1OL Amphilimna olivacea (Lyman) (fig. 79D), a long- armed species of moderate size (10 mm disc), that belongs to the subclass Ophiuroidea, family Ophio- canthidae. It is a moderately deepwater inhabitant, which we found only in the northern sector of the region along the Outer Continental Shelf and upper slope. BATHYMETRIC DISTRIBUTION TOTAL MACROBENTHIC FAUNA OF ALL TAXONOMIC GROUPS ENTIRE MIDDLE ATLANTIC BIGHT REGION A pronounced decrease in total macrobenthos (that is, a summation of all taxonomic categories) was associated with an increase in water depth from the shallowest to deepest water depth classes. This re- lationship applied to both the number of individuals and the biomass. Consistent trends of decreasing quantities, as the depth increased within all three subareas, revealed the general nature and wide- spread occurrence of this relationship (figs. 80 and 81). (See table 8.) TABLE 8.-Number of samples within each depth range class in each subarea and for the entire Middle Atlantic Bight region Depth Subarea Entire ranges 8011112;er $1531 22:51; region (m) England Bight Bight 0-24 "Ll...... 35 46 84 165 25-40 ._________ 27 48 48 123 50-99 ..________ 56 47 15 118 100-199 ________ 19 9 6 34 200-499 ._______._ 14 8 6 28 500-999 _______- 8 T 10 25 1,000-1,999 ___.... 11 10 13 24 2,000-3,080 ______- 16 12 8 36 Total: ...... 186 187 190 563 Number of individuals.-The density of macro- benthic invertebrates was highest - (averaged 2,079/m>) in the shallowest depth class, 0-24 m, and decreased to 46/m': in deep water (2,000- 3,999 m), a 98 percent reduction. Table 9 lists the mean number of individuals and biomass for each TABLE 9.-Mean number of individuals and biomass of the macrobenthic invertebrate fauna in relation to water depth for each subarea and for the entire Middle Atlantic Bight region Water depth Mean number of individuals per square meter Mean biomass in grams per square meter (meters, to nearest in) SNE NYB CHB Entire area SNE NYB CHB _ Entire area 0424 _. 1 . _._. esa theis 2,426 2,480 1,742 2,079 404 804 114 368 BDAUN . _...... 3,090 752 722 1,254 343 123 102 163 50409 ._.. ..._ 2,988 1,390 795 2,078 287 166 80 189 1004190 / _.. .. .- ole 934 442 969 810 89 36 109 79 2004400. 468 255 350 382 34 17 28 28 5004000 . 251 206 387 293 17 T 11 12 1100041,009 .........L.__..._..~_.~. 75 66 75 (2 5 5 11 T 2000-8080 ._..........-......-..- 48 47 40 46 8 T 10 8 N102 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES 0 100 icomerers - g Echinagrachnius parma A P __¢ a J ‘f’ 5 19 e E § » s e_ _s" @ Cl) ® & A U C U U a a" :* "~- U / a- / 1 l / / I lI ' e _/ P ®" U I, [6S ¢ i i (\ ®{ I A4, s \ I v 1 i ( I \ 16 « # »| Astropecten spp p ~ , ___| Amphilimna olivacea FIGURE 79.-Geographic distribution (indicated by dots) of selected echinoids (A4, B), asteroids (C), and ophiuroids (D), phylum Echinodermata. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N103 \ SLOPE ----»|- RISE SHELF I T I I I I I 3000|- IX\\‘>§ c g EXPLANATION J- goon ! mune Here ee (s SNE xX X o N Y B - aA -----A 25 00|- & L6 CHB - 0 5 ENTIRE 6 w AREA L 5 - 2000- - L C < ~> aj M C _ 1500|- ~- LJ Qa A wel < bee O° _ 1i00o0o|- - 2 C < LL. @ o 500|- mel Lu [en] 3 mn p 0 | | | I 1 | rmmumed .. O 25 50 100. 200 500 fooo 2000 4000 WATER DEPT H, IN-ME T ERS FIGURE 80.-Relationship between number of individuals and water depth. Values represent all taxonomic groups combined for each subarea and for the entire Middle Atlantic Bight region. Abbreviations: SNE, Southern New England; NYB, New York Bight; CHB, Chesapeake Bight. of eight water-depth classes for the entire Middle Atlantic Bight region (columns 5 and 9), and for each subarea. Density decreased substantially, although somewhat irregularly, as the depth in- creased on the Continental Shelf. At midshelf, the average density ranged from 1,254/m> to 2,073/m, and along the outer shelf it dropped to 810/m'. Den- sity of organisms declined further on the Continental Slope. Along the upper slope, the faunal density averaged at midslope 293/m', and on the lower slope 72/m*. The decline continued onto the Continental Rise, where macrobenthic organisms N104 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES 8 70 0|- 6 00|- 500 400|- 300- 2 00f- 1 0 0}|- WET WEIGHT, IN GRAMS PER SQUARE METER OF BOTTOM EXPLANATION SNE X ---- X a N Y B _ A --- CHB Q- -->}. 0 ENTIRE ias 500 1000 2000 4000 WATER DEPTH,IN MET ERS FIGURE 81.-Relationship between biomass (wet weight) and water depth. Values represent all taxonomic groups combined for each subarea and for the entire Middle Atlantic Bight region. Abbreviations: SNE, Southern New England; NYB, New York Bight; CHB, Chesapeake Bight. averaged only 46/m'. Although there were regional variations in density, which are described below, the trend in density with respect to water depth was clear. Density was highest in the most shallow water and varied inversely with water depth. The rate of change in density as related to bath- ymetric changes is not readily perceived from the values listed in table 9. Therefore, another tabulation (table 10) was constructed in which the rate of change in density-expressed as the increase or de- crease in number of individuals per square meter of bottom, per meter increase in water depth-was calculated and listed. The rate changes in density per unit change in water depth were greatest on the Continental Shelf. A decrease of 33 individuals per meter increase in water depth occurred in inner- shelf waters, from 0-24 m to 24-49 m. At midshelf depths, the rate of change was spurious, and reversed to an increase of 22 individuals per meter. Modest rate changes (about -17 individuals per meter) in density were found in the Outer Continental Shelf region. Only small changes from (-0.2 to -0.3 1 t MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N105 TABLE 10.-Change and rate of change in density of invertebrates in relation to water depth Water depth Number Change in Rate change Range Mean Change of number of in number of individuals individuals individuals m m m No. /m No. /m No.. /m2 /m 0-24 12.5 - 2,078.66 - - 25-49 27.5 26 1,253.64 -825.02 -33. 00 50-99 75 37.56 2,072.87 +819.23 *21.85 100-199 150 75 809.68 -1263.19 -16.84 200-499 350 200 381.68 - 428.00 - 2.14 500-999 750 400 292.76 - 88.92 - 0.22 1,000-1,999 1,500 750 72.38 - 220.38 - 0.29 2,000-3,999 2,540 1,040 45.75 - 26.63 - 0.026 TABLE 11.-Change and rate of change in biomass of invertebrates in relation to water depth Water depth Change Rate change Range Mean Change Biomass in biomass in biomass per meter depth m m m g/m g/m 0-24 12.5 - 368 - - 25-49 37.5 25 163 -205 -8.20 50-99 75 37.5 189 *+ 26 +0. 69 100-199 150 75 79 -110 -1.47 200-499 350 200 28 - 51 -0.26 500-999 750 400 12 - 16 -0. 04 1,000- 1,999 1,500 750 7 -* -0.007 2,000- 3,999 2,540 1,040 8 + 1 +0. 001 N106 individual per meter increase in depth) were evident on the Continental Slope. Very small changes (-0.026 specimen per 1l-meter) were detected on the Continental Rise. Biomass.-The relationship between invertebrate macrobenthic biomass and water depth (table 9, last column) parallels the pattern described above for density. Biomass was greatest (averaged 8368 g/m') in the shallowest depth class. It decreased irregularly across the shelf, where average values ranged from 163 g/m to 189 g/m at midshelf, and averaged 79 g/m along the Outer Continental Shelf. Biomass on the Continental Slope ranged from 7 g/m on the lower slope to 28 g/m on the upper slope. On the Continental Rise, the biomass aver- aged 8 g/m'. The rate of change in biomass per 1-m increase in water depth was greatest in shallow water and least in deepwater. This is evident, in the rate- change column of table 11. The average biomass diminished 8.2 g/m" for each meter of water depth, from the shallowest depth class (0-24 m) to the next deeper depth class (25-49 m). At midshelf, the biomass showed an increase, which was probably caused by regional differences in biomass (described below) and which, to some extent, reflects the larger standing crop of several taxonomic groups (Gastro- poda, Ophiuroidea, Alcyonacea, and others) along the Outer Continental Shelf. The rate of biomass change on the Outer Continental Shelf averaged -1.5 g/m per 1-m increase in depth. The rate of change diminished progressively down the slope: -0.26, -0.04, and -0.007 g/m. On the Continental Rise, there was a slight increase in biomass rate-change (+0.001 g/m); but this, again, was probably due to the regional differences in biomass and to the few samples that were collected. The trend of decreasing biomass as water depth increases was clearly evident. Despite a few irregu- larities, the reduction in biomass, from an average of 368 g/m in shallow water to 8 g/m in deep water, amounts to a 98 percent change. This is pre- cisely the same change described for the density of organisms. SUBAREAS SOUTHERN NEW ENGLAND The number of individuals was, on the average, substantially higher in Southern New England than in the other subareas. This is evident from the density values given in table 9, column 2, and plotted in figure 80. On the Continental Shelf, the average ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES density for each bathymetric class in the subarea ranged from 934/m' to 3,090/m', and the overall average was 2,360/m', whereas shelf densities for the entire Middle Atlantic Bight region ranged from 810/m' to 2,079/m' and averaged only 1,554/m*. The comparative average values for New York Bight and Chesapeake Bight were 1,254/m* and On the Continental Slope, the faunal density, also, was moderately high compared with that of other subareas. The density of the Continental Slope fauna in Southern New England averaged 265/m*, compared with 249/m> for the entire Middle Atlantic Bight region, 171/m" for New York Bight, and for the Chesapeake Bight. The density of organisms on the Southern New England Conti- nental Rise averaged 48/m', a quantity only slightly higher than densities in the other subareas (40/m to 47/m?) and for the entire Middle Atlantic Bight region The standing-crop biomass on the Continental Shelf and Upper Continental Slope in the Southern New England subarea was considerably greater than the Middle Atlantic Bight region averages (table 9 and fig. 81). Biomass averages for four depth classes on the Continental Shelf ranged from 89 to 404 g/m, and the overall average was 268 g/m'. That quantity was only slightly less than the 282 g/m found in New York Bight, but much greater than the 101 g/m* found in Chesapeake Bight. For midshelf depths between 25 and 99 m, the quantities of biomass in Southern New England (which averaged 237 and 343 g/m*) surpassed the amounts found in the other subareas. Biomass on the Continental Slope was greater (average 19 g/m) in Southern New England than in either New York Bight (10 g/m?) or Chesapeake Bight (17 g/m>). The mean biomass of 8 g/m* on the Conti- nental Rise in this subarea was average for the entire region. It was slightly higher than that for New York Bight (7 g/m) and slightly lower than that for Chesapeake Bight (10 g/m). NEW YORK BIGHT The number of individuals in the New York Bight subarea fell between that in Southern New England and in Chesapeake Bight (table 9 and fig. 80) on the Continental Shelf. Densities averaged between 442/m? and 2,430/m>; overall average was 1,254/m'. This density compares with 1,554/m> for the entire Middle Atlantic Bight region, 2,360/m* for Southern New England, and 1,057/m' for Chesapeake Bight. Highest densities, as expected, were in the shallowest MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION depth class (0-24 m). Unusually low densities, com- pared with those from adjacent bathymetric classes and adjacent subareas, of 752/m> and were found on the Continental Shelf at water depths be- tween 25 and 49 m and 100 to 199 m (table 9, column 3). Faunal densities in these two depth classes were roughly one-half the density expected. The cause of these unusually low densities was the sparsity of representatives in several taxonomic groups. (See discussion under "Taxonomic Groups.") Fauna on the Continental Slope of the New York Bight subarea, also was relatively sparse, compared to other subareas. Densities ranged from 66/m' to 255/m', and averaged 176/m'. This overall average is about 35 percent below the average slope density for both Southern New England and Chesapeake Bight. The faunal density of 47/m' on the Continental Rise was nearly equal to that in the other two sub- areas. Biomass in New York Bight fell between those in the Southern New England and Chesapeake Bight subareas. Unusually large and small quantities were found in the various bathymetric classes. On the Continental Shelf, the biomass ranged from the un- commonly small quantity of 36 g/m on the outer shelf to the unexpectedly large 804 g/m in the inshore region. Although the overall quantity of biomass for the Continental Shelf, which averaged 282 g/m", was highest in the region, this was due largely to the influence of shallow-water components. A biomass of 123 g/m near midshelf was substan- tially lower-about 50 percent-than was antici- pated. Also, the outer shelf biomass (36 g/m) was smaller than expected by at least 100 percent. These small biomass values correspond to the low densities of the fauna in the New York Bight subarea de- scribed above. Biomass on the Continental Slope ranged from 5 to 17 g/m, and averaged only 10 g/m. This is sub- stantially less than the quantities found in adjacent subareas, which averaged 19 g/m? in Southern New England and 17 g/m in Chesapeake Bight. On the Continental Rise, the average biomass of 7 g/m was smaller than that found in adjacent sub- areas, which averaged 8 and 10 g/m> respectively in Southern New England and Chesapeake Bight. New York Bight biomass was 13 percent and 30 percent smaller than counterpart values in the adjacent sub- areas. A discussion of the taxonomic components that were in short supply or unusually plentiful is in- cluded in "Taxonomic groups." N1O7 CHESAPEAKE BIGHT The number of individuals was slightly lower in this subarea than in New York Bight and much lower than in Southern New England. The average density in the various bathymetric classes on the Continental Shelf ranged from 722/m' to 1,742/m>', which was generally lower than in other subareas, and overall averaged only 1,057/m'. Comparative quantities in Southern New England and New York Bight were 2,360/m% and respectively. Unusually low densities of 722/m> and 795/m" were found at midshelf depths; conversely, an unex- pectedly high density (969/m*) was found on the outer shelf. On the Continental Slope, the faunal density was relatively high, averaging and ranging from to These densities were slightly higher than those at comparative depths in Southern New England and much higher than those in New York Bight. On the Continental Rise, the faunal density aver- aged 40/m*", which was slightly less than densities at this bathymetric level in the other subareas. The biomass of the benthic fauna in Chesapeake Bight was substantially less than that in other parts of the Middle Atlantic Bight region. Average values for the various depth classes on the Continental Shelf ranged from 80 to 114 g/m". This subarea, with its rather narrow Continental Shelf, did not have the marked difference in biomass between inshore shallow water regions and the outer shelf margin that was so pronounced in both Southern New Eng- land and New York Bight. Thus, Chesapeake Bight is somewhat different from the other subareas in two aspects; it is characterized by: (1) a small biomass on the Continental Shelf and a rather large biomass on the slope and rise; and (2) little differ- ence in biomass from shallow to deepwater on the Continental Shelf. Biomass on the Continental Slope was moderately high, ranging from 28 g/m? on the upper slope to 11 g/m on the lower part. The average for the entire slope was 17 g/m. This value was slightly lower than that for Southern New England (19 g/m"), but much higher than that for New York Bight, which averaged only 10 g/m. Biomass on the Continental Rise averaged 10 g/m. This was the highest for this depth class in any subarea in the entire Middle Atlantic Bight region. N108 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 12.-Mean number of individuals listed by major taxonomic groups for each bathymetric class, representing the entire Middle Atlantic Bight region [In number per square meter] Taxonomic group Bathymetric class (meters) 0-24 25-49 50-99 100-199 200-499 500-999 1,000-1,999 2 3,999 no./m2 no./m2 no./m2 no./m2 no./m2 no./m2 no./m2 n0./m2 PORIFERA 1.25 0. 52 0.07 0.74 0.21 0.08 0.12 0.06 COELENTERATA 34.93 8.96 9.03 40.76 13.90 4.52 3.88 1.11 Hydrozoa 19.58 6.90 2.13 27.71 3.96 0.08 - - Anthozoa 15. 35 2.06 6.90 13.05 9.94 4.44 3.88 1:11 Alcyonacea 0.01 ~ 0.52 2.76 1.61 1.20 0.97 0.61 Zoantharia 5.01 1.13 5.63 9.44 5.04 1.76 0.06 0.17 Unidentified 10.33 0.93 0.75 0.85 3.29 1.48 2.85 0.33 PLATYHELMINTHES Turbellaria 1.70 0.21 0.43 - - - - = NEMERTEA 5.30 5.87 6.27 2.74 1.64 0.72 1.21 0.11 ASCHELMINTHES Nematoda 5.01 0.94 3-21 0.47 0.82 2.52 0.50 0.64 ANNEL IDA 472.07 <265.75- 352.66 238.26 178.00 61.84 17.26 6.44 POGONOPHORA - 0.55 0.05 - 21.32 5.21 2.53 SIPUNCULIDA 0.96 4.63 5.54 9.85 11.89 2.00 2.06 1.31 ECHIURA 0.27 0.02 - - - - 0.35 0.72 PRIAPULIDA - - - - - - 0.24 - MOLLUSCA 911.14 61.79 183.62 192.97 87.03 187.52 34.03 26.63 Polyplacophora 0.52 0.05 0.95 - 0.07 0.60 0.71 0.28 Gastropoda 9§.52 13.95 11.54 13.47 9:21 18.40 2.59 1.25 Bivalvia 815.01 47203 ~ 169.37 '[171.74 70.18 161.40 29.79 12.69 Scaphopoda 0.76 0.86 2.50 7.39 7.12 0.94 - Cephalopoda - - - 5.26 0.18 ~ - - Unidentified - - 0.90 - - - =- - ARTHROPODA 552.99 B03.12 1414.19 62.64 45.13 6.68 1.27 2.77 Pycnogonida 1:33 0.46 0.22 0.06 - - - - Arachnida 0.16 ~ - - - - - =- Crustacea 551.50 802.66 1413.97 62.58 45.13 6.68 1.27 2.77. Ostracoda 0.57 0.02 0.18 - - - - 0.17 Cirripedia 101.98 0.60 0.03 - - - - = Copepoda - - 0.08 - 0.21 0.20 - - Nebaliacea - - 0.05 - - - - 0.06 Cumacea 1.99 31.43 36.36 8.82 4.68 0.48 0.35 0.69 Tanaidacea - - - - 0.18 i 0.06 0.72 Isopoda 17.57 20.96 11.25 1.76 1.14 0.96 0.18 0.19 Amphipoda 407.47 . 742.20 1361.25 49.35 38.46 4.96 0.62 0.94 Mysidacea 6.90 0.11 0.02 - 0.07 ~- - - Decapoda 15.02 7.34 4.75 2.65 0.39 0.08 0.06 - BRYOZOA 25.34 33.99 3.47 0.15 - - - - BRACKHIOPODA - - 0.02 - f - - - ECHINODERMATA 42.88 41.82 78.33% | 235.59 28.21 2.88 2.65 6.48 Holothuroidea 0.70 0.14 5.90 2.06 9.46 0.52 0.62 0.39 Echinoidea 41.14 40.24 10.20 1.03 0.46 - 0.06 0.17 Ophiuroidea 0.73 0.38 61.03 . 231.03 17.86 2.20 1.62 5.86 Asteroidea 0.31 1.02 2.10 1.47 0.43 0.16 0.35 0.06 HEMI CHORDATA 0.15 - 0.35 0.15 - 0.20 - - CHORDATA Ascidiacea 11.79 35.28 9.91 19.50 1.29 - 0.76 2.58 UNIDENTIFIED 12.88 5.66 4.81 5.85 6.32 2.48 2.85 6.78 TAXONOMIC GROUPS ENTIRE MIDDLE ATLANTIC BIGHT REGION The quantitative distribution of each phylum and 28 major subcomponents (classes and orders) as they were related to eight bathymetric classes are listed in tables 12 and 13 and are shown graphically in fig- ures 82-87. The data pertain to the entire Middle | Atlantic Bight region; later sections deal with simi- lar relationships within each subarea. They were relatively sparse in New York Bight, and were present in intermediate quantity in Chesapeake Bight. Hydrozoa were common on the Continental Shelf in all subareas, but were rare below 500 m. The MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N109 TABLE 13.-Mean biomass listed by major taxonomic groups for each bathymetric class, representing the entire Middle Atlantic Bight region [In grams per square meter] Taxonomic group Bathymetric class (meters) 0-24 25-49 50-99 100-199 200-499 500-999 1,000-1,999 2 ,000- 3,999 g/m __ g/m g/m __ g/m g/m g/m g/m g/m PORIFERA 0.036 0.190 <0. 001 0.033 0.018 <0.001 0.019 0.035 COELENTERATA 4.653 1.419 1.297 - 14.986 1.020 0.303 0.464 0.513 Hydrozoa 0. 860 0.130 0.055 0.025 0.048 0.001 - - Anthozoa 3.793 1.289 1.242 - 14.962 0.972 0.302 0.464 0.513 Alcyonacea 0.012 - 0.172 0.428 0.083 0.107 $.221 0.048 Zoantharia 3.588 1.175 0.892 14.431 0.721 0.164 0.048 0.198 Unidentified 0.192 0.114 0.179 0.103 0.169 0.031 0.196 0.266 PLATYHELMINTHES 0.011 0.006 0.012 =- - - - - Turbellaria 0.011 0.006 0.012 - - - - - NEMERTEA 0.878 0.884 0.637 0.297 0.106 0.012 0.193 0.001 ASCHELMINTHES 0.006 0.023 0.005 0.003 0.004 0.011 0.004 0.004 Nematoda 0.006 0.003 0.005 0.003 0.004 0.011 0.004 0.004 ANNEL IDA 15.339 12.830 20.002 7.452 7.907 5.280 0.786 0.404 POGONOPHORA - 0.003 <0.001 a 0.056 0.145 0.020 0.010 SIPUNCUL IDA 0.125 0.293 1.033 0.218 1.003 3.488 2.082 0.451 ECHIURA 0.175 0.015 - - - - 0.664 2.414 PRIAPULIDA - - - - - - 0.147 - MOLLUSCA 301.965 94.611 122.904 - 16.566 2.140 1.187 0.450 0.233 Polyplacophora 0.474 0.006 0.013 - <0.001 0.004 0.008 0.005 Gastropoda 6.789 0.876 4.202 0.055 0.135 0.171 0.031 0.0093 Bivalvia 294.703 93.709 118.671 16.404 1.863 0.914 0.400 0.218 Scaphopoda 0.022 0.014 0.034 0.140 0.098 0.011 - Cephalopoda - - - 0.072 0.002 - - - Unidentified - - 0.004 - - - ~ - ARTHROPODA 19.213 7.963 7.551 0.674 0.226 0.080 0.042 0.031 Pycnogonida 0.009 0.001 0.001 0.001 - - - - Arachnida 0.001 - - - = - - - Crustacea 19.203 7.962 7.549 0.674 0.226 0.080 0.042 0.031 Ostracoda 0.005 <0. 001 0.001 - - - - 0.001 Cirripedia 12.774 0.015 <0. 001 - - - - - Copepoda - - <0.001 - 0.001 0.002 - - Nebaliacea - - <0.001 - - - - 0.001 Cumacea 0.014 0.095 0.192 0.055 0.027 0.005 0.004 0.014 Tanaidacea - - - - 0.002 - 0.001 0.005 Isopoda 0.138 0.761 0.347 0.130 0.046 0.008 0.005 0.002 Amphipoda 3.526 5.583 6.659 0.276 0.141 0.048 0.004 0.008 Mysidacea 0.030 0.002 <0. 001 - 0.001 - - - Decapoda 2.716 1.506 0. 350 0.213 0.008 0.017 0.029 - BRYOZOA 0.555 0.684 0.079 0.002 - e - = BRACHIOPODA - - 0.0C1 - - - - - ECHINODERMATA 13.757 38.227 33.734 |- 35.478 15.516 1.026 2358 3.433 Holothuroidea 0.076 0.504 20.831 6.260 5.334 0.027 1.132 2.739 Echinoidea 11.578 37.411 4.352 13.498 6.560 - 0.107 0.233 Ophiuroidea 0.255 0.031 2.601 14.212 3.611 0.995 0.998 0.461 Asteroidea 1.848 0.282 5.950 1.509 0.005 0.004 0.116 0.001 HEMICHORDATA 0.041 - 0.066 0.044 - 0.002 - - CHORDATA 7.077 5.801 0.924 2.608 0.054 - 0.004 0.399 Ascidiacea 7.077 5.801 0.924 2.608 0.054 - 0.004 0.399 UNIDENTIFIED 0.238 0.376 0.412 0.140 0.064 0.148 0.197 0.084 quantity of hydroids varied only modestly from one subarea to another, except for the irregular oc- currence of very high or low densities, which may have resulted from the vagaries of sampling. Both density and biomass revealed the same intersubarea trends; slightly higher quantities in Southern New England, lower quantities in New York Bight, and intermediate quantities in Chesapeake Bight. Anthozoa, as a group, were distributed much the same, in relation to the bathymetric level, in all three subareas. However, one of the main subgroups, the Alcyonacea, presented a different pattern. They were common at middepths and in deep water (50 to 3,999 m) in Southern New England and New York Bight, but in Chesapeake Bight they were found only in very shallow (0-24 m) and very deep (1,000- 3,999 m) waters. Platyhelminthes occupied the same bathymetric classes in all three subareas. The largest quantities, in terms of both density and biomass, were found N110 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES PORIFERA ~-----7 ------ ZOANTHARIA 410.20 1O|- 1.4} A @mam No. & 114 'This WTC L ® £ [- K s 40.15 i 12 pS t.OF- 410 0 ol: @ p3 i 0.8|- a 10.10 o © # 0 a [- - ~- $- ® 0.6 s 3 & 'a co S 0.4} <10.05 -| 4 A A 21 A re & 0.2} /\o epl "4+ \2\ o\ o 5 % ol t ___I >. * Nez" | o F z A~-a-fem ma 1] o 6 L; - L cenas, L tof HYDROZOA mgt PLATYHELMINTHES poze > u A we | (s o a < 40|- < 3 t Sr- -440.015 as o 410.6 g 30- i o o A # 1.0} 410.010 p a 20—- © —0.4 a. C "lox 0.5|- loos.) . 2 1g 10|- * ® < 3 \ / & 0 gl1=-4 _i _ o pleas selten. ct & # Fa a. y ( T C n SF ALCYONARIA -~~~~TJpgs sf 4 EMERTEA > A +- a -40.8 > 4|- 410.4 8}|- 5 & 'a L -10.6 % 3}- 40.3 6|- - e g ./. Lu > 40.4 i & 2} 10.2 a} E: - 0.2 |- /2\ lo. 2 \. A A\./.\ OM; mdc (} ol- | 1 I 1 I\A . | & | _| 0 0 |: "50 | -200 j 1000 4000 0 | '50 .; 200-1000 11000 2D 100 500 : 2000 20 100 500 - 2000 WATER DEPTH, IN METERS Ficur® 82.-Density (No.) and biomass (wt.) in relation to water depth in the entire Middle Atlantic Bight region for Porifera, Hydrozoa, Alcycnaria, Zoantharia, Platyhelminthes, and Nemertea. in Southern New England, lowest amounts in New | metric level in all subareas. In terms of density, York Bight, and intermediate quantities in Chesa- | Nemertea ranked first in Southern New England peake Bight. with an average of ranked second in New Nemertea were distributed similarly (as described | York Bight with 2.6/m', and were least abundant in the preceding section) in regard to the bathy- | in Chesapeake Bight with 0.4/m*. Biomass values MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION NILL fo NEMATODA SIPUNCULA 5 415 <10.014 14} @mmm No. SC | "«- Wi <10.012 12) /. -|4 - -]0.010 (ea & * O 6 |- 413 s - _ (< ae 6 0.008 8 / s O - 3 ab l <10.006 6} 'A 412 ye & oA o’. 8 s \ a e a~~4 40.004 4} 'I "of. A\ f. $= 9" a <0.002 2|- A U"" 0 53 & 4 ta 4 o | ® _ | y®="*® i_|;, o -* i%, _; & LJ LJ i 0 sppfe *- ANNELIDA sC T G- ECHIURA js.c s 3 a -<|30 C LJ < 412.5 a z 400|- -|os 0.8}- A < 0 6 3 w 412.0 O ool % /‘ 4120 0.6} n &C # Ld & -| 5 1,86 E 5 200}- 'a' A oa} a in & 41.0 U3 e ioo} ""‘\ ® 0.2|- al fr . -I - 3 k o & o L U 1 i __ _ @Azoe _| | o 0 | O LJ a. 3 in r---- POGONOPHORA ----7 PRIAPULIDA h 25|- 10.20 1.OF- 410.20 > L_ T O $ (0) 20} 64% 0.8 |- bars e a 'A 749 A A* LLJ 3 co 15}- 0.6 |- + < -l a L > 0.10 0.10 R < 1 Of- oa - Ga 0.05 © 40.05 5} 3 0.2 |- / A\. \A ok _- Mrs iol _ Les _n ( LLE SBL .. ce ha S.. . . tlt 0 | 50 | 200 j 1000 | 4000 0 | 50 | 200 | 1000 | 4000 256 100 500 2000 25 100 500 2000 WATER DEPTH, IN METERS FIGURE 83.-Density (No.) and biomass (wt.) in relation to water depth in the entire Middle Atlantic Bight region for Nematoda, Annelida, Pogonophora, Sipuncula, Echiura, and Priapulida. biomass 0.007 g/m?) than in the other two subareas. In New York Bight, their distribution was irregular, and they were present in relatively small quantities (average density of 0.1/m" and biomass less than 0.001 g/m). In Chesapeake Bight, nematodes were reflected the same sequential order, with average values of 0.8 g/m, 0.7 g/m, and 0.3 g/m. Nematoda were more widely distributed bathy- metrically and were found in larger quantities in Southern New England (average density and N112 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES prs POLYPLACOPHORA o-- SCAPH --- 1.0 P4 410.5 1 Of- OPODA 10.20 A @ mmm NO. ost A- Wt. dog sl- 10.15 # u * e /. aA "@ D o6}- o 410.3 6|- > # " 3 -|0.10 o 0 0.4|- 10.2 f. i- c 4 s CO LL & 0.2|- ® ; oF <|0.05 a § . ¥ e ¥ / s ol- t --i + a-=ax~s_ 1‘9‘7‘, Bi st oa t ls 4 C §, o o T 0 Gs i- > 5 LJ foor GASTROPODA ——q7 orn CSPHALOPGBDA --- Clos i L o ‘ A LJ < 78 & 3 80f- 8|- a ed slg -l0.06 =, 7 (a) 6o}|- A sla 6|- 92 CC L al & i #3 0.04 a 40}|- 4|- a % x" 0.02 34 Z GV. = 20}|- 2} < L C3 t < 3 04 un g 5 '\./ \ t it 5 o | A -A--A-@=@A o GL | 1 ; tA _; | ns l (9 O e BNALMIAGE---.- PYCNOGONIDA s t & VALVI 41300 a us AS Llo- 1250 I “0.008 LID soo} 1.2} ig C , -|2 00 1.0} 10.006 * c 60 0|- p- 0.8|- LJ bs -| 150 = 2 410,004 I 400|- A 0.6- % e <100 R C l \ 40.002 f wm / A ( ~ \\i o o" , * n~~£ --- the o _s .t - @ - _ Com _ lg 6 ; 50 $:2700 , 1Ggo ; 4000 o . j 5p ,; apo ; teso | 40ge 295 100 500 2000 22 100 500 2000 WATER DEPTH, IN METERS FIGURE 84.-Density (No.) and biomass (wt.) in relation to water depth in the entire Middle Atlantic Bight region for Polyplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda, and Pyenogonida. slightly irregular in distribution, and the quantity Annelida were widely distributed in all subareas. fell between those in Southern New England and | They were most abundant in Southern New England, those in New York Bight (density averaged 2/m* | intermediate in New York Bight, and relatively and biomass 0.006 g/m). sparse in Chesapeake Bight. An exceptionally high MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N113 rin ------- NEBALIACEA for OSTRACODA———jo'006 cnet NEBALIACE @ mam No * 410.005 p- 0.08|- 0.8 An mone: WT . sp:.0006 > 410.004 A O 0.6} 0.06|- w @ o 3 (~ 10.003 @ 10.0004 S 8 04|- 0.04|- A he 410.002 O L c 6 bo2|- 40.0002 is 9°f o & 40.00! § 3 C 6 lg/ 1 I L | I 1 1 | 1 1 I | L | | &C we ol- 0 0 0 L L; i- bse LJ CIRRIPEDIA Sop CUMACEA YABo < L 100 ® -|14 A C LJ < o -l12 40 |- < CD) sol- € 40.15 3 w 4110 gol © 7 60|- ix -| 8 - & 5 I 0.10 p L 4o_ - 6 20'- a_ & o o -| 4 410.05 s Lw 20 |- 10|- \ 2 -| 2 © Z a \:S 4 & 0 ol L_ @@ L 11 0 b 1) p o : o > L a e- in gr- COPEPODA Acooss 9% TANAIDACEA £ boos ig LL L 0 «& 0.8}- 40.0020 0.8 |- 410.004 e o i B LJ c 0.6 - 410.0015 0.6) 410.003 - s il w 3 3 z 04}- 410.0010 0.4} 40.002 A 0.2|- & ms € -|0.0005 02~- \ 40.001 ® z/ \A 0 L 1 1 | 1 I | | 1 O 0 1 H L L 1 L 1 & H 1 O O | 50 | 200 | 1000 | 4000 0 :4. 50 |. 200 | 1000 | 4000 28 100 500 - 2000 25 100 500 - 2000 WATER DEPTH, IN METERS FiguUrE 85.-Density (No.) and biomass (wt.) in relation to water depth in the entire Middle Atlantic Bight region for Ostracoda, Cirripedia, Copepoda, Nebaliacea, Cumacea, and Tanaidacea. density of annelids occurred in the shal- | New England averaged 19 g/m", New York Bight low waters (0-24 m) of New York Bight, as com- | 13 g/m, and Chesapeake Bight 9 g/m. pared with the other subareas where the density at Pogonophora were found primarily in deepwater this depth averaged and 183/m'. Biomass | (200 to 3,999 m) in all three subareas. Density and trends were similar to those of density; Southern | biomass were approximately equal in Southern New N114 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES 25+“ ISOPODA 352 A& s¢: # meme Wt. 40.6 3 [> > 1500 w @ -<14 A C g 1000} -3 A ® -|2 & > soo|- ./ Lu - & <10.4 C LJ <410.3 i 410.2 n y 10. 1 < 0.10 410.0020 o F— X (&] 0.08|- LTJ -|0.0015 3 0.06 £- LJ A& 10.0010 - z 0.04} <10.0005 0.602} P O L 1 1 1 | L 1 1 1 O 0 | 50 ; 200 ; 1000 -| 40060 22 100 500 : 2000 WATER DEPTH, IN METERS FigurE 86.-Density (No.) and biomass (wt.) in relation to water depth in the entire Middle Atlantic Bight region for Isopoda, Amphipoda, Mysidacea, Decapoda, Bryozoa, and Brachiopoda. England and New York Bight, but were three to four times more abundant in Chesapeake Bight. In the two northern subareas, the density of pogono- phorans averaged approximately 5/m> in the deep water, whereas in Chesapeake Bight their average density was 16/m'. On the Continental Shelf in Chesapeake Bight, pogonophorans were found in un- usually shallow water. Live specimens and tubes were taken from water as shallow as 66 m, and tubes only were present at 43 m. Sipunculida were widely distributed bathymet- rically in all three subareas, but there was a marked MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N115 HOLOTHUROIDEA Uo Oma No, f) 'the . VY t, _ al 25 ps3 A 4120 O 6- F. . 4/15 O c si 410 LL O it SF “\A l -| 5 i- 0 o LJ w. --- ECHINOIDEA ig 50 y 40 C < J i 40}- 0 ~130 o 30;- & 10 120 o. 20|- A > & <\\ -|10 l 1 o} A\ > A 0 o * o LJ a th,, : - pre- OpHUunpipeA LL A -I | 4 O 250|- a o 12 C LJ 200|- -11 0 c < 1 50|- 1° ~> C -| 6 100- -| 4 50|- / - 2 / A—A\ 0 0 05} | 200 | 1000 | 4000 29 100 500 - 2000 seF ASTEROIDEA 37 416 2.0|- <5 ad 414 = C -|3 -|2 c 0.5- L5 <1 \ *y -»* A ¥ olLL_LS IL __|__ | Acle _ 1 Jp (s) to iof HEMICHORDATA r- pal L o.s|- s 40.06 3 (e) o.6|- (€ <0.04 fe LJ 0.4} a. a; / \ 40.02 (2 0.2} C3 * o o g CC 0 id I | 1 | | & | | 0 O Z el 50|- 18 s e nd A € = 30|- p- LW _.4 g 20}|- 0 o | 50 | 200 | 1000 | 4000 25 - 100 500 2000 WATER DEPTH, IN METERS FIGURE 87.-Density (No.) and biomass (wt.) in relation to water depth in the entire Middle Atlantic Bight region for Holothuroidea, Echinoidea, Ophiuroidea, Asteroidea, Hemichordata, and Ascidiacea. difference in density and biomass. Density was high- est (average about in Southern New England, intermediate (3/m?) in New York Bight, and lowest (1.5/m?) in Chesapeake Bight. Trends in biomass were nearly the same; largest (1.4 g/m?) in Southern New England and substantially lower (0.4 and 0.8 g/m) in New York Bight and Chesapeake Bight. Echiura were found in both very shallow (less than 50 m) and very deep (greater than 1,000 m) water in two subareas, New York Bight and Chesa- N116 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 14.-Mean number of individuals listed by major taxonomic groups for each bathymetric class, representing the Southern New England subarea [In number per square meter] Taxonomic group Bathymetric class (meters) 0-24 25-49 50-99 100-199 200-499 500-999 1,000-1,999 _ 2,000-3,999 No. /m No. /m2 No. /m2 No. /m2 No. /m No. /m2 No . /m No . /m2 PORIFERA 2.60 3.37 =- 1.32 0.43 0:25 0.18 0.13 COELENTERATA 113.40 4.75 12.23 19.68 15.64 3.00 3.18 9.51 Hydrozoa 13.20 2.19 0.82 - 2.86 - ~- - Anthozoa 40.20 2.56 11.41 19.68 13.28 3.00 3.18 0.91 Alcyonacea = - 1.05 2.42 2.14 0.50 0.45 0.25 Zoantharia 3.40 2.04 9.79 16.47 9.64 - 0.18 0.13 Unidentified 36.80 0.52 0.57 0.79 1.50 2.50 2.55 0.13 PLATYHELMINTHES 6.77 0.22 0.50 - - - - - Turbellaria 6.77 0.22 0.50 - - - - - NEMERTEA 3.06 12.00 9.96 3.47 2.07 0.75 2.09 0.13 ASCHELMINTHES 17.97 1.56 6.66 0.84 0.86 5.13 0.18 0.75 Nematoda 17.97 1.56 6.66 0.84 0.86 5.13 0.18 0.75 ANNELIDA 315.54 647.37 484.36 333.63 254.93 106.00 13.73 7.19 POGONOPHORA = ~ - - 7.14 10.38 2.64 1.56 SIPUNCUL IDA 4.49 20.15 7.70 15.32 18.79 2.50 0.18 1.50 ECHIURA * =- - - - - 0.91 0.38 PRIAPULIDA = - - - - - 0.54 - MOLLUSCA 478.97 91.36 209.01 134.01 72.43 106.13 44.18 12.07 Polyplacophora 2.14 0.22 1.89 ~ ~ 0.25 0.64 0.13 Gastropoda 135.83 46.07 19.43 2.11 9.14 13.13 2:78 0.25 Bivalvia 340.57 45.07 185.80 120.74 55.50 91.25 40.45 11.69 Scaphopoda = - 1.74 7.43 1.50 0.36 - Cephalopoda = = - 9.42 0.36 - - - Unidentified = - 1.89 - - - - - ARTHROPODA 1370.57 - 2146.64 2080.46 61.59 45.14 10.13 1.45 3:63 Pycnogonida 1.23 1,37 0.21 =- - 4 a G Arachnida + = e e = = - - Crustacea 1369.34 '. 2145,2¢ 2080.25 61.59 45.14 10.13 1.45 3.63 Ostracoda 1.11 ~ 1.37 ~- s e - - Cirripedia 107.46 2.41 - - = - - - Copepoda = = 0.11 - 0.43 0.63 - - Nebaliacea = = - - £ = - - Cumacea 1.26 88.30 49.18 7.53 3.07 0.75 0.36 1.00 Tanaidacea - - - - 0.36 - 0.18 0.88 Isopoda 4.94 36.67 10.46 1.37 0.93 2.50 0.18 0.31 Amphipoda 1220.31 2008.67 2015.79 52.16 39.71 6.25 0.73 1.44 Mysidacea 7:03 0.11 - - > - - - Decapoda 27.28 9:11 3.34 0.53 0.64 - - BRYOZOA 83.29 73.63 0.29 0.26 = - - - BRACHIOPODA = ~ - - y - - - ECHINODERMATA 4.12 39.49 154.71 321.11 40.51 3.00 3.18 8.63 Holothuroidea 1.03 - 11.71 2.11 8.86 a 1.00 0.25 Echinoidea 1.29 34.89 14.68 1/42 0.79 - 0.18 0.38 Ophiuroidea 0.89 0.89 125.14 316:47 30.29 3.00 1.64 8.00 Asteroidea 0:11 3.81 3.18 asil 0.57 - 0.36 - HEMICHORDATA = = 0.73 0.26 £ 0.63 - Fs CHORDATA 20.69 73.63 15.30 34.58 2:43 - 1.36 2:31 Ascidiacea 20.69 13.63 15.30 34.58 2.43 =- 1.36 2.31 UNIDENTIFIED 4.26 16.93 7.09 1 +63 3.50 1155 9.25 peake. Bight. In Southern New England they were present only in deep water, 1,000 to 1,999 m. Den- sities were low in all areas in both shallow and deep water. Biomass, however, was larger (1.3 to 6.7 g/m*) in deep water than in shallow water; also it was larger in New York Bight and Chesapeake Bight than in Southern New England, where the average quantities were less than 0.5 g/m. Priapulida were rare; they were taken in only two subareas, Southern New England and Chesapeake Bight. All samples were from the same bathymetric class-1,000 to 1,999 m. Densities were less than MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION TABLE 15.-Mean biomass listed by major taxonomic groups for each bathymetric class, representing the Southern New England subarea [In grams per square meter] NILT Taxonomic group Bathymetric class (meters) 0-24 25-49 50-99 100-199 200-499 500-999 1,000-1,999 2,000-3,999 g/m g/m? g/m g/m2 g/m g/m g/m g/m PORIFERA 0.147 0.478 - 0.059 0.035 0.002 0.002 0.079 COELENTERATA 5.640 2.264 2.117 23.411 31.412 0.054 0.429 2.478 Hydrozoa 2.933 0.287 0.081 - 0.142 - - - Anthozoa 2.708 1.977 2.036 31.270 0.054 0.429 2.478 Alcyonacea - - 0.361 0.435 0.081 0.005 0.116 0.004 Zoantharia 1.833 1.950 1.542 22.935 31.126 - 0.148 2.091 Unidentified 0.875 0.027 0.133 0.040 0.062 0.049 0.166 0.382 PLATYHELMINTHES 0.036 0.003 0.016 - - ~ - - Turbellaria 0.036 0.003 0.016 - - - - - NEMERTEA 0.752 2.010 1.013 0.232 0.164 0.011 0.103 0.001 ASCHELMINTHES 0.003 0.008 0.010 0.005 0.005 0.015 0.002 0.006 Nematoda 0.003 0.008 0.010 0.005 0.005 0.015 0.002 0.006 ANNEL IDA 23.800 24.373 31.012 10.416 5.575 3.276 0.796 0.299 POGONOPHORA - - - - 0.089 0.032 0.011 0.369 SIPUNCUL IDA 0.588 1.126 1.412 1.142 1.453 10.676 0.012 1.003 ECHIURA - - - ~ - - 0.472 0.267 PRIAPUL IDA - - - - - - 0.361 - MOLLUSCA 294.898 263.083 131.102 4.572 2.004 0.958 0.524 0.312 Polyplacophora 2.207 0.025 0.027 - - 0.002 0.008 0.001 Gastropoda 4.088 2.238 7.914 0.013 0.054 0.076 0.049 0.004 Bivalvia 288.598 260.820 123.154 4.403 1.831 0.858 0.460 0.306 Scaphopoda - ~ 0.027 0.115 0.021 0.006 - Cephalopoda - - - 0.129 0.004 - - - Unidentified ~ - 0.008 - - - - - ARTHROPODA 53.305 16.668 10.685 0.533 0.224 0.058 0.024 - Pycnogonida 0.006 0.002 0.002 - - - - - Arachnida - - - - - - - - Crustacea 53.299 16.665 10.682 0.533 0.224 0.058 0.024 0.049 Ostracoda 0.011 - 0.002 - - - - - Cirripedia 38.960 0.056 - - - - - - Copepoda - - <0.001 - 0.003 0.006 - - Nebaliacea - - - - - - - - Cumacea 0.020 0.277 0.269 0.056 0.014 0.008 0.004 0.026 Tanaidacea - - - - 0.004 - 0.002 0.006 Isopoda 0.053 0.616 0. 343 0.095 0.047 0.019 0.013 0.003 Amphipoda 10.558 13.957 9.827 0.377 0.144 0.025 0.006 0.014 Mysidacea 0.045 0.001 - - - - - - Decapoda 3.652 1.758 0.241 0.005 0.013 - - - BRYOZOA 1.917 2.756 0.044 0.003 - - - - BRACHIOPODA - - - - - - - - ECHINODERMATA 13.141 4.560 57.353 44.956 23.066 1.714 1.307 4.586 Holothuroidea 0.101 - 43.353 3.342 3.950 - 0.331 3.579 Echinoidea 12.277 4.229 2.261 17.123 12.991 = 0.332 0.525 Ophiuroidea 0.489 0.058 5.312 22.570 6.118 1.714 0.519 0.482 Asteroidea 0.274 0.274 6.427 1.922 0.006 - 0.126 - HEMICHORDATA - - 0.139 0.080 - 0.006 - - CHORDATA 9.697 24.289 1.666 4.625 0.106 - 0.007 0.369 Ascidiacea 9.697 24.289 1.666 4.625 0.106 - 0.007 0.369 UNIDENTIFIED 0.095 1.138 0.066 0.195 0.100 0.035 0.466 0.142 0.6/m* and biomass less than 0.4 g/m"; occurrence records were too few to make comparisons. Mollusca were abundant in terms of the number of individuals and were dominant in biomass in all three subareas. A comparison of each molluscan class, by subarea, is presented separately. Densities of Polyplacophora were low in all sub- areas. Relatively, they were more numerous in Southern New England, where the average density was 1/m'. In New York Bight, they were found in only two depth classes (50-99 m and 2,000-3,999 m), and their average density was low-O0.1/m' to 0.5/m*. In Chesapeake Bight, they were present in five depth classes, and their average density ranged from 0.1/m* to 1.3/m'. Biomass, also, was small in all areas; values ranged from 0.001 to 2.2 g/m and were generally proportional to the densities. Gastropoda were one of the more common com- ponents of the Mollusca. In each subarea, they showed a similar distribution in relation to water N118 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 16.-Mean number of individuals listed by major taxonomic groups for each bathymetric class, representing the New York Bight subarea [In number per square meter] Taxonomic group Bathymetric class (meters) 0-24 25-49 50-99 100-199 200-499 500-999 1,000-1,999 2,000-3,999 No. /m2 No. /m No. /m2 No.. /m No.. /m2 No . /m2 No . /m2 No . /m2 PORIFERA 1.02 0.94 0.17 - - > w 2 COELENTERATA 19.54 6.06 4.42 9.33 7:81 10.29 1.80 1.58 Hydrozoa 11.26 4.65 1.40 2.00 ~- 0.29 - > Anthozoa 8.28 1.41 3.02 7.33 7 $1 10.00 1.80 1.58 Alcyonacea - - 0.04 5.33 1.88 3.71 1.60 0.75 Zoantharia 8.28 0.60 2,38 0.67 0.75 6.29 - 0.33 Unidentified = 0.81 0.60 1.33 4.88 > 0.20 0.50 PLATYHELMINTHES 0.04 9.13 0.09 - - - ¥ & Turbellaria 0.04 9.13 0.09 - - - s F NEMERTEA 3.30 4.17 2.556 1.78 0.50 0.29 - 0.17 ASCHELMINTHES f 0.04 9.13 - 1.13 0.29 0. 60 - Nematoda - 0.04 0.13 - 1.13 0.29 0.60 - ANNEL IDA 1119.52 136.60 265.94 127.22 113.88 43.43 24.10 7.33 POGONOPHORA =- - - - 1.25 9.71 3.80 3. 50 SIPUNCUL IDA - 0.50 4.32 4.89 7.50 1.29 2.80 0.50 ECHIURA 0.52 = = t - - - 0.83 PRIAPULIDA = = € - = - - - MOLLUSCA 652.31 54.94 109.88 117.87 86.00 129.43 23.60 20.66 Polyplacophora y + 0.13 - - - x 0.50 Gastropoda 62.46 4.31 5.38 44.44 12.25 31.29 3.80 233 Bivalvia 589.85 50.63 102.61 68.99 64.25 86.00 18.40 17.83 Scaphopoda - f 1.76 4.44 9.50 12.14 1.40 - Cephalopoda fs % = = * - ~ - Unidentified s = = x = - - - ARTHROPODA 488.05 492.13 978.18 48.67 22.89 4.57 1.20 2.37. Pycnogonida 0.24 = h - - - - =- Arachnida 0.57 = =- - - - - = Crustacea 487.24 492.13 978.18 48.67 22.89 4.57 1.20 2.17, Ostracoda 1.15 = = - - - e e Cirripedia 283.48 - 0.06 - P a s a Copepoda & = 0.09 - - % a ite Nebaliacea = 5 a C x = h 0.17 Cumacea 2.07 3/38 25.27 13.78 2.38 - 0.60 0.75 Tanaidacea p: = £ - # = in s Isopoda 5.43 21.73 13.69 2.44 2 A3 - 0.20 - Amphipoda 171.09 459.10 932.10 23.78 18.13 4.57 0.20 0.92 Mysidacea 3.61 0.17 0.04 = 0.25 - - = Decapoda 20.41 7.156 6.93 8.67 - - 0.20 a BRYOZOA 11.91 3.83 4.04 ~- - = £ ¥ BRACHIOPODA = = al = = 3 e - ECHINODERMATA 120.65 38.79 10.84 125.67 13.75 3.00 2.70 3:33 Holothuroidea 1.07 0.04 0:77 1.11 6.50 0.29 0.40 0. 50 Echinoidea 118.04 38.44 5.08 0.89 0.25 = a a Ophiuroidea 0.61 - 3.59 123.00 6.75 2.71 2.10 2.83 Asteroidea 0.93 0.31 1.40 0.67 0.25 - 0.20 Fe HEMICHORDATA 0:28 = & = = =- - - CHORDATA 1.24 13.52 5.57 0.67 0.25 > = 3.33 Ascidiacea 1.24 13.52 5.57 0.67 0.25 > + 3.33 UNIDENTIFIED 11.89 0.77 0.79 5.56 0.50 3.29 5.00 3.08 depth. Densities generally were highest (29/m>) in Southern New England, intermediate (21/m>) in New York Bight, and lowest (16/m*) in Chesapeake Bight. Biomass reflected this same trend of decreas- ing abundance, 1.8 g/m in the north to 1.0 g/m in the south. Bivalvia were different from many other major taxa in having the highest densities (averaging 300/m*) in the Chesapeake Bight subarea, inter- mediate densities (averaging in New York Bight, and lowest densities (averaging in Southern New England. Particularly high densities MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION NA19 TABLE 17.-Mean biomass listed by major taxonomic group?) for each bathymetric class, representing the New York Bight subarea [In grams per square meter] Bathymetric class (meters) Taxonomic group 0-24 25-49 50-99 100-199 200-499 500-999 1,000-1,999 2,000-3,999 a/m a/m2 g/m? g/m? g/m? a/m2 g/m g/m PORIFERA 0.010 0.092 0.002 - - - = = COELENTERATA 2.956 0. 380 0.439 7.119 0.551 0.966 0.164 0.625 Hydrozoa 0.179 0.050 0.024 0.027 - 0.003 - - Anthozoa 2.776 0. 330 0.415 7.092 0.551 0.963 0.164 0.625 Alcyonacea - - 0.001 0.699 0.185 0.376 0.104 0.032 Zoantharia 2.776 0.202 0. 362 6.092 0.122 0.587 - 0. 307 Unidentified - 0.128 0.052 0. 301 0.244 - 0.060 0.286 PLATYHELMINTHES 0.002 0.004 0.004 - - - - - Turbellaria 0.002 0.004 0.004 - - - =- = NEMERTEA 2.048 0.711 0.183 0.152 0.011 0.003 - 0.002 ASCHELMINTHES - <0. 001 0.001 - 0.002 0.003 0.006 - Nematoda - <0. 001 0.001 - 0.002 0.003 0.006 - ANNEL IDA 31.180 7.980 11.257 3.956 10.350 3.149 0.894 0.723 POGONOPHORA - - - - 0.008 0.046 0.030 0.012 SIPUNCULIDA - 0.116 0.858 0.522 0.934 0.083 0.194 0.007 ECHIURA 0.519 =- - - - - - 2.400 PRIAPUL IDA - - - - - - - - MOLLUSCA 710.785 41.072 131.048 2.738 2.264 1.011 0.515 0.226 Polyplacophora - - 0.001 - - - - 0.012 Gastropoda 7.897 0.426 1.073 0.167 0. 346 0.133 0.030 0.014 Bivalvia 702.888 40.646 129.944 2.507 1.708 0.687 0.469 0.199 Scaphopoda - - 0.030 0.064 0.210 0.191 0.016 - Cephalopda - - - - - - - - Unidentified - - - - - - - - ARTHROPODA 23.438 5.669 5.667 1.162 0.163 0.113 0.110 0.018 Pycnogonida 0.005 - - e - - - - Arachnida 0.003 - - = - - h - Crustacea 23.430 5.669 5.667 1.162 0.163 0.113 0.110 0.018 Ostracoda 0.010 - =- = - - = e Cirripedia 16.175 - 0.001 - - - - - Copepoda - - <0.001 - - =- = - Nebaliacea ~ - ~ - - ~ - 0.002 Cumacea 0.017 0.014 0.127 0.080 0.016 - 0.006 0.007 Tanaidacea - - - - - - - 0.003 Isopoda 0.075 0.874 0. 394 0.234 0.076 - 0.002 - Amphipoda 2.678 2.831 4.579 0.059 0.068 0.13 0.002 0.007 Mysidacea 0.016 0.004 <0. 001 - 0.002 - - - Decapoda 4.458 1.947 0.565 0.789 - - 0.100 ~ BRYOZOA 0.206 0.153 0.052 - - - - - BRACHIOPODA - - - - - - - - ECHINODERMATA 32.851 66.242 8.434 19.354 2.590 1.154 3.459 2.472 Holothuroidae 0.132 0.145 0.629 0.098 0.571 0.013 2.487 1.906 Echinoidea 25.864 65.592 7.472 14.844 0.226 - - - Ophiuroidea 0.435 - 0.184 4.246 1.790 1.141 0.724 0.567 Asteroidea 6.420 0.505 7.244 0.781 0.002 = 0.248 - HEMICHORDATA 0.022 - - - - - - - CHORDATA 0.094 0.791 0.294 0.100 0.002 - - - Ascidiacea 0.094 0.791 0.294 0.100 0.002 - b 0.544 UNIDENTIFIED 0. 376 0.229 0.264 0.113 0.005 0.471 0.044 0.025 (1,136/m>* and 590/m*) in Chesapeake Bight and New York Bight were found in shallow water, 0-24 m. Differences in density, associated with water depth, were the same in each subarea. Biomass aver- aged nearly the same in the three subareas; it was only slightly higher (average 109 g/m') in New York Bight, and about equal (84 and 85 g/m') in creases in biomass as the water depth increased were generally similar in all subareas. Scaphopoda were present in moderately deep water in all subareas. They were present in highest density (5.8/m*) in New York Bight, and about equal densities (approximately 3/m*) in Southern New England and Chesapeake Bight. Biomass of Chesapeake Bight and Southern New England. De- | scaphopods was small in all subareas and the relative N120 quantities were similar to their density. Largest biomass (average 0.1 g/m*) was in New York Bight, and substantially smaller quantitiee (about 0.04 g/m?) were present in Southern New England and Chesapeake Bight. Cephalopoda, which were represented by benthic eggs, were present only in Southern New England. They were taken at water depths between 100 m and 499 m. Highest density (average 9.4/m>) was taken at 100 to 199 m, and lowest density (average 0.4/m?) was taken in deeper water. Biomass averaged 0.12 g/m along the Outer Continental Shelf and 0.004 g/m on the Continental Slope. Arthropoda were represented principally by Crus- tacea; only minor quantities of Pyenogonida and Arachnida were present in the samples. Pyenogonida occurred in shallow water only; from 0 m to 99 m in Southern New England, 0 m to 24 m in New York Bight, and 0 m to 199 m in Chesa- peake Bight. Density was low (0.2/m*) in New York Bight, and Pycnogonida were taken only in Long Island Sound. Densities in Southern New England and Chesapeake Bight were roughly similar, and averages ranged from 2.0/m> to 0.2/m> in each sub- area. Highest densities were in shallow water, and lowest densities were in deep water in each subarea. Biomass of pycnogonids was very small (equal to or less than 0.01 g/m?) in all subareas. Trends of bio- mass in relation to water depth were similar to those for density. Arachnida were incompletely sampled because of their small size. They were present only in New YorkBight where their average density was less than 0.6/m* and biomass less than 0.008 g/m. Crustacea were the single most numerous taxo- nomic group in all three subareas. Average density in the various bathymetric classes ranged from 1/m' to and tended to decrease as water depth increased. Density differences from one sub- area to another were substantial; highest densities were found in Southern New England, intermediate densities in New York Bight, and lowest densities in Chesapeake Bight. Biomass was moderate, rang- ing from an average of 0.006 g/m in deep water to 53 g/m in shallow water. Differences in biomass from one subarea to another were similar to those of density. Biomass in Southern New England aver- aged 16 g/m; in New York Bight, 9 g/m; and in Chesapeake Bight, 3 g/m. Ostracoda were incompletely sampled, but showed a similar pattern of occurrence in each subarea. They were present only in shallow water, 0 to 99 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES m, and always in low density (1.4/m* or less). Bio- mass was extremely small, averaging 0.01 g/m or less. Cirripedia were present only in shallow water (less than 99 m) in all subareas. Because of their spotty distribution and highly clustered occurrence, their density varied considerably from one subarea to another and between bathymetric classes. Highest average density (283/m*) was found in 0 to 24 m in New York Bight, intermediate density (107/m>) in 0 to 24 m in Southern New England, and low density (less than 1/m>) in Chesapeake Bight. In water deeper than 24 m, their density was low (maximum of 2.4/m?) in all subareas. Biomass of barnacles was largest (39 g/m") at 0 to 24 m in Southern New England, intermediate (16 g/m") in New York Bight, and very small (less than 0.0083 g/m) in Chesapeake Bight, and was small to very small in all subareas at water depths greater than 25 m. Copepoda were incompletely sampled because of their small size. In Southern New England,they were taken at three depth classes (50-99 m, 200-499 m, and 500-999 m); in New York Bight, they were taken at one depth class (50-99 m), and none were taken in Chesapeake Bight. Average density and biomass in all localities were very small-maximum values 0.6/m* and 0.003 g/m, respectively. Nebaliacea were incompletely sampled. None were taken in Southern New England. A few were taken in very deep water (2,000 to 3,999 m) in New York Bight, where their density averaged 0.17/m'. A few specimens were taken at water depths of 50 to 99 m in Chesapeake Bight, where their density averaged Biomass was very small, equal to or less than 0.003 g/m. Cumacea were widely distributed bathymetrically and geographically. Their bathymetric distribution was similar in all subareas, but their density, and biomass to a limited extent, differed from one sub- area to another. Cumaceans were most abundant in Southern New England, where their average density was and their biomass was 0.13 g/m'. Ap- proximately equal densities (average 8/m' and respectively) and biomass (average 0.045 and 0.035 g/m*) were present in New York Bight and Chesapeake Bight. Tanaidacea were present only in deep water and at low densities (0.18/m? to 1.0/m?). In New York Bight and Chesapeake Bight, they were present only in very deep water (2,000-3,999 m), but in Southern New England they were found in both deep water MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N121 TABLE 18.-Mean number of individuals listed by major taxonomic groups for each bathymetric class, representing the Chesapeake Bight subarea [In number per square meter] Taxonomic group Bathymetric class (meters) 0-24 25-49 50-99 100-199 200-499 500-999 1,000-1,999 2,000-3,999 No. /m No. /m2 No. /m No. /m No. /m2 No. /m No. /m2 No. /m2 PORIFERA 0.82 0.17 - - - - 0.15 - COELENTERATA 10.67 14.25 11.47 154.66 18.33 1:70 6.07 1.63 Hydrozoa 1.80 11.81 9.27 154.00 13.00 - - - Anthozoa 8.87 2.44 2.20 0.66 5.33 1.70 6.07 1.63 Alcyonacea 0.02 - h - - - 0.92 1.13 Zoantharia 3.89 1.15 0.27 9.33 - - - - Unidentified 4.96 1.29 1.93 0.33 5.33 1:70 5.156 9.50 PLATYHELMINTHES 0.50 0.29 1.27 - - - - - Turbellaria 0.50 0.29 1:27 - - ~- - - NEMERTEA F: 4 4.13 $.13 1.83 2.17 1.00 1.38 - ASCHELMINTHES 2.356 1:50 - - 0.33 2.00 0.69 1.38 Nematoda 2136 1.50 - - 0.33 2.00 0.69 1.38 ANNEL IDA 182.73 236.48 132.73 102.83 84.00 39.40 15.00 3.63 POGONOPHORA - 1.42 0.40 - 15.33 38.20 8.46 3.00 SIPUNCULIDA 0.02 0.04 1.33 - 1.67 2.10 3.08 2.13 ECHIURA 0.25 0.04 ~ - - - 0.15 1.28 PRIAPUL IDA - - - - - - 9.13 - MOLLUSCA 1232.94 52.00 219.53 492.50 122.49 293.30 33.47 8.88 Polyplacophora 0:13 - - - 0.33 1.30 1.31 Gastropoda 96.82 5.52 1.40 3.00 5.53 13.60 1.54 1.63 Bivalvia 1135.99 44.54 316.93 487.50 j12.33 270. 30 29.54 7.00 Scaphopoda - 1.94 1.20 2.00 4.50 8.10 1.08 - Cephalopoda - - - - - - - - Unidentified - - - - - - - - ARTHROPODA 247.89 358.40 293.80 86.99 74.83 5.40 1.15 2.00 Pycnogonida 1.96 0.42 0.93 0.33 - - - - Arachnida - - - - - - - - Crustacea 245.93 357.98 292.87 86.66 74.83 5.40 1.15 2.00 Ostracoda 0.02 0.04 - - ~- - - 0.75 Cirripedia 0:31 0.19 - - - - - - Copepoda - - - - - - - - Nebaliacea f - 0.40 - - - - - Cumacea 2.26 27.50 23.13 5.50 11.50 0.60 0.15 - Tanaidacea - - int = - - - 1.00 Isopoda 29.48 11.35 6.47 2.00 0.33 0.40 0.15 0.25 Amphipoda 198.23 312.90 259.67 78.83 62.67 4.20 0.85 - Mys idacea 8.65 0.06 - - - - ~ - Decapoda 6.98 5.94 3.20 0.33 0.33 0.20 - - BRYOZOA 8.55 2.31 13.73 - - - - - BRACHIOPODA - - 0.13 - - - - - ECHINODERMATA 16.45 45.98 11.74 129.67 18.83 2.79 215 6.88 Holothuroidea 0.04 0.31 0.27 3:33 14.83 1.10 0.46 0.50 Echinoidea 15.63 45.04 9.53 n - - - - Ophiuroi dea 0:73 0.48 1.67 125.67 3.67 1.20 1.23 6.13 Asteroidea 0.05 9.15 0.27 0.67 0.33 0.40 0.46 0.25 HEMICHORDATA 0.13 - - - - - - - CHORDATA 13.87 0.79 3.33 - - - 0.85 2.00 Ascidiacea 13.87 0.79 3.33 - - - 0.85 2.00 UNIDENTIFIED 17.01 4.21 1.27 0.67 12.00 1.10 231 7.38 (1,000-3,999 m) and at middepths (200-499 m). Biomass, also, was small at all localities (0.003 to 0.006 g/m?), and no geographic differences were apparent. Isopoda were distributed in the same bathymetric pattern and at roughly equal densities in all sub- areas. In each subarea, the high densities, which ranged from 22/m to 36/m*, were found in shallow water (0-49 m) ; intermediate densities at middepths (50-999 m); and low densities, 0.3/m* to 0.2/m', were found in deep water (1,000 m or deeper). Bio- mass was small (maximum bathymetric class aver- N122 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 19.-Mean biomass listed by major taxonomic groups for each bathymetric class, representing the Chesapeake Bight subarea [In grams per square meter] Bathymetric class (meters) Taxomonic group 0-24 25-49 50-99 100-199 200-499 500-999 1,000-1,999 2,000-3,999 g/m g/m g/m g/m2 g/m2 g/m g/m g/m PORIF ERA 0.004 0.126 - - - - 0.048 - COELENTERATA 5.170 1.984 0.923 0.110 0.352 0.039 0.725 0.165 Hydrozoa 0.369 0.120 0.055 0.100 0.035 - - - Anthozoa 4.802 1.864 0.868 0.010 0.317 0.039 0.725 0.165 Alcyonacea 0.024 - - - - - 0.399 0.160 Zoantharia 4.764 1.713 0.121 0.007 - = f - Unidentified 0.013 0.150 0.747 0.003 0.317 0.039 0.326 0.005 PLATYHELMINTHES 0.006 0.003 0.021 - - - ~ - Turbellaria 0.006 0.009 0.021 ~- - = - - NEMERTEA 0.289 0.423 0.653 0.720 0.100 0.018 0.417 - ASCHELMINTHES 0.009 0.002 - - 0.003 0.014 0.005 0.008 Nematoda 0.009 0.002 ~ - 0.003 0.014 0.005 0.008 ANNEL IDA 10.996 11.186 6.298 3.312 10.092 8.374 0.694 0.134 POGONOPHORA - 0.009 0.001 - 0.047 0.305 0.020 0.010 SIPUNCUL IDA <0. 001 <0. 001 0.163 - 0.043 0.120 5.287 0.011 ECHIURA 0. 060 0.038 - - - - 1.336 6.731 PRIAPULI DA - - ~ - - - 0.078 - MOLLUSCA 81.043 53. 362 66.783 75.288 2.295 1.493 0.338 0.084 Polyplacophora 0.011 - - b 0.003 0.008 0.014 0.002 Gastropoda 7.304 0.558 0.148 0.018 0.042 0.273 0.015 0.012 Bivalvia 73.728 52.772 66.619 75.257 2.147 1.118 0.297 0.069 Scaphopoda - 0.032 0.016 0.013 0.103 0.094 0.012 - Cephalopoda - - - - - - - - Unidentified - - - - - - - - ARTHROPODA 2.694 5.361 1.785 0.392 0.317 0.074 0.006 0.012 Pycnogonida 0.012 0.001 0.003 0.003 - h - = Arachnida - - - - - - - - Crustacea 2.682 5.360 1.752 0.388 0.317 0.074 0.006 0.012 Ostracoda <0. 001 <0.001 - - - - - 0.005 Cirripedia 0.002 0.008 - - - - = =- Copepoda - - - - - - - - Nebaliacea - - 0.003 - = + = # Cumacea 0.011 0.075 0.105 0.017 0.072 0.006 0.002 - Tanaidacea - - - - - - - 0.005 Isopoda 0.208 0.730 0.216 0.083 0.003 0.004 0.002 0.002 Amphipoda 1.060 3.624 1.350 0.282 0.235 0.022 0.003 - Mysidacea 0.030 0.001 - - - - - - Decapoda 1.371 0.922 0.079 0.007 0.007 0.042 - - BRYOZOA 0.179 0.049 0.291 - - = = = BRACHIOPODA - - 0.001 - = = a a ECHINODERMATA 3.556 29.148 2.598 28.728 15.138 0.378 2.386 2.568 Holothuroidea 0.035 1.145 0.047 24.745 14.940 0.059 0.766 2.308 Echinoidea 3.462 27,895 2.381 - a - - = Ophiuroidea 0.059 0.046 0.053 2.693 0.192 0.318 1.613 0.258 Asteroidea <0. 001 0.062 0.116 1.290 0.007 0.001 0.007 0.002 HEMICHORDATA 0.068 - - - - - - - CHORDATA 9.809 0.412 0.125 - - - 0.003 0.242 Ascidiacea 9.809 0.412 0.125 - - - 0.003 0.242 UNIDENTIFIED 0.223 0.094 0.021 0.003 0.060 0.011 0.087 0.058 land, it averaged 7.0 g/m"; in New York Bight, it age was 0.6 g/m*) in all bathymetric classes in each averaged 2.5 g/m; and in Chesapeake Bight, it aver- subarea. Amphipoda were the most abundant taxonomic group in the Middle Atlantic Bight region. Major differences in density were found from one subarea to another. In Southern New England, they were most numerous, averaging in New York Bight, they were moderately common, averaging 396/m'; and in Chesapeake Bight, they were least numerous, averaging 192/m'. Biomass, also, differed from one subarea to another. In Southern New Eng- aged only 1.5 g/m*. Relationships of density and bio- mass to water depth were very similar among the three subareas. Mysidacea, although incompletely sampled, re- vealed the same trend of decreasing density as water depth increased in all three subareas. They were taken only at depths less than 500 m, but were most com- mon at depths from 0 to 24 m, where their average density ranged from 8.6/m' to 8.6/m'. In water MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION depths greater than 25 m, their average density ranged from 0.25/m> to 0.4/m*. Biomass was small (maximum bathymetric class average 0.04 g/m) in all subareas. Decapoda revealed a bathymetric distribution pat- tern that was similar in each subarea. They were regularly taken at depths from 0 to 200 m, but only occasionally at greater depths. The density of deca- pods was about the same (8/m*) in Southern New England and New York Bight, but substantially lower in Chesapeake Bight. Biomass was largest (1.6 g/m?) in New York Bight, intermediate (1.1 g/m?) in Southern New England, and smallest (0.8 g/m?) in Chesapeake Bight. The trends of den- sity and biomass in relation to water depth were similar in all subareas. Bryozoa had much the same bathymetric distribu- tion in all subareas. In Southern New England, they were found in each bathymetric class on the Con- tinental Shelf (0-199 m), and in New York Bight and Chesapeake Bight, they were found at depths from 0 to 99 m. Density was much higher in South- ern New England (overall average of 39/m*) than in the other subareas, where the average was about 6/m' to 8/m in each. Biomass was relatively high in Southern New England, where it averaged 1.2 g/m, compared to an average of less than 0.2 g/m in New York and Chesapeake Bights. Brachiopoda were absent in the Southern New England and New York Bight subareas; they were present in only one sample from Chesapeake Bight at a depth of 91 m. Echinodermata were very common in all subareas and were present in all bathymetric classes. Echi- noidea and Ophiuroidea were the two dominant sub- groups. These and the other two major classes are described below. Holothuroidea were widely distributed bathy- metrically as well as geographically. They were pres- ent in all depth classes from the shallowest to deep- est. The pattern of density distribution in relation to depth was the same in each subarea. Highest density (1/m' to occurred along the Outer Continental Shelf and upper slope and decreased in both shallower and deeper water. The biomass of the holothurians was substantially greater in South- ern New England than in the other subareas. On the outer shelf and upper slope off Southern New England, their average biomass ranged between 28 and 51 g/m. In New York Bight, their average biomass was less than 0.7 g/m> at these bathymetric levels. In Chesapeake Bight, their average biomass at all depths was 7 g/m and was largest (15 to 25 N123 g/m) at depths between 100 and 500 m. Biomass in very deep water (greater than 1,000 m) averaged about 2 to 3 g/m in all subareas, whereas in shallow water, 0 to 50 m, the average quantity usually was smaller than 1 g/m. Echinoidea showed a pronounced decrease in den- sity from shallow to deep water. This relationship between density and water depth was the same in all subareas; however, echinoids were found across the shelf into deep water (at depths greater than 2,000 m) in Southern New England, to moderate depths (500 m) in New York Bight, and to only 99 m in Chesapeake Bight. Average densities were highest (bathymetric class average up to 118/m>) in New York Bight, intermediate in Chesapeake Bight, and slightly lower in Southern New England. Echinoids accounted for a major share of the bio- mass, especially in New York Bight, where inner shelf quantities averaged 26 g/m and 66 g/m. In Southern New England, biomass averages on the inner shelf were 4 g/m? and 12 g/m; and in Chesa- peake Bight, were 3 g/m and 28 g/m. Ophiuroidea were distributed bathymetrically much the same in each subarea. High density (aver- ages of 123/m> to occurred at middepths, and decreased to densities of less than 1/m in shal- low shelf waters, and to 1/m2 to 8/m* in very deep water (greater than 1,000 m). Biomass was largest, averaging up to 22 g/m, in Southern New England; intermediate in New York Bight; and smallest (0.5 to 2.7 g/m) in Chesapeake Bight. Trends in density and biomass in relation to water depth were the same in all subareas. Asteroidea had a rather low density and a wide bathymetric range in all subareas. The general rela- tionship between density and water depth was a relatively high density (0.7/m> to 4/m*) at mid- depths, 25 to 200 m, and low density (0.2 /m: to in shallower and deeper waters. Overall density was highest in Southern New England, in- termediate in New York Bight, and lowest in Chesapeake Bight. Although their density was mod- est, asteroids constituted a substantial biomass at middepths, which was largest in Southern New Eng- land, averaging 2 to 17 g/m; intermediate in New York Bight, averaging 0.8 to 7 g/m; and smallest in Chesapeake Bight, averaging 0.1 to 1.2 g/m. Hemichordata were sparse in all subareas and in all bathymetric classes (a total of 6) in which they were found. Average densities were less than 0.7/m*, and average biomasses were less than 0.14 g/m. In Southern New England, their bathymetric range was from 50 to 999 m, whereas in New York Bight and N124 Chesapeake Bight, they were found only in very shallow (0 to 24 m) waters. Chordata (Ascidiacea) were widely distributed bathymetrically and geographically. In all three sub- areas, density was highest on the Continental Shelf, lowest on the Continental Slope, and intermediate on the Continental Rise. Densities were substantially higher (average in Southern New England than in both New York Bight (average 5/m>) and Chesapeake Bight (average 7/m*). Trends in bio- mass of ascidians were similar to those in density; largest quantities were found in Southern New Eng- land (average 5.8 g/m), smallest in New York Bight (average 0.3 g/m*), and intermediate quantities in Chesapeake Bight (average 2.1 g/m). RELATION TO BOTTOM SEDIMENTS DISTRIBUTION OF SEDIMENT TYPES The geographic distribution of bottom sediments in the Middle Atlantic Bight region is shown in figure 88. (See table 20 for number of samples for each type of bottom sediment.) The most striking feature of these distributional patterns is the preva- lence of sand on the Continental Shelf throughout the entire region. Silt and clay sediments predomi- nate in the deeper waters, especially on the Conti- nental Slope and Rise. Sediments in the bays and sounds are characterized by their wide diversity of types. Gravel was relatively rare and found only in Southern New England. Sand-gravel was uncommon and found mainly in Southern New England and New York Bight. Shell sediments, also, were rela- tively rare; they were found only in Chesapeake Bight. Sand-shell mixtures were moderately com- mon, especially in New York Bight and Chesapeake Bight. Although sand sediments were present throughout much of the entire region, they were especially widespread on the Continental Shelf. They TABLE 20.-Number of samples for each bottom-sediment tyne in each subarea and for the entire Middle Atlantic Bight region Subarea Bottom Southern New Chesa- Entire sediments ew York peake region England Bight Bight Gravel 3 0 0 3 Sand-gravel _______ 11 5 2 18 Shell "_...... 1 0 8 4 Sand-shell _________ 1 16 27 44 Sand == 83 118 84 285 Silty sand __.... 52 18 24 94 SHE L see cud. 25 16 28 69 CAY, +a eae anne is i 10 14 22 46 Total A.s-.s. 186 187 190 563 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES were the dominant sediment type in shelf waters in all subareas. Silty sand was common on the outer shelf off Southern New England and along the Con- tinental Slope in all subareas. Silt was most common on the Continental Slope, but also was found in sub- stantially large areas on the Continental Rise. Clay sediments were dominant on the Continental Rise in all subareas and were present in limited areas on the Continental Slope. The bathymetric distribution of sediments throughout the entire region showed a decided de- crease in particle size as depth increased. The coarser grained substrates, gravel and shell, were confined to water depths of less than 50 m; sand- gravel substrates were not found in depths beyond 100 m; and sand-shell was restricted to depths of less than 200 m. Sand was present at depths down to a maximum of 500 m. Among the finer grained substrates, silty sand was ubiquitous throughout the entire bathymetric range. Silts, also, were present at nearly all depths. Clay sediments were found in bays, sounds, and coastal areas down to a depth of 49 m, and although they were absent from most of the shelf and upper slope areas, they were present from midslope (500 m) down to the deepest depths sampled. Photographs of the sea bottom (figs. 89 to 94) taken with the Campbell grab photographic system show the sediment surface in different bottom types. Three of the photographs show the camera-tripping weight, which stirs up fine particles when it strikes bottom. One of these photographs shows coarse sedi- ments and two show fine-grained sediments. The presence or absence of fine-grained particles in sus- pension provides an indication of the amount of silt- clay in the sediment. TOTAL MACROBENTHIC FAUNA OF ALL TAXONOMIC GROUPS ENTIRE MIDDLE ATLANTIC BIGHT REGION The relation of density and biomass of all or- ganisms to bottom sediments in the entire Middle Atlantic Bight region is depicted in figures 95 and 96. Density tended to decrease as particle size de- creased (table 21, fig. 95). Average densities ranged from a high of 2,667/m in gravel to a low of 165/m in clay. Intermediate values were present in sedi- ment types of intermediate particle sizes. Sand- gravel contained an average of 2,089/m*, whereas shell contained 1,639/m*. The average density for sand-shell was 2,006/m*; and sand, silty sand, and silt contained an average of and respectively. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION EXPLANATION Gravel Sand -gravel 200m - FIGURE 88.-Geographic distribution 0 " A 0 a* of bottom-sediment types Bight region. in the Middle Atlantic N125 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES FicuUrRE 89.-Gravel bottom at a depth of 23 m in the Nantucket Shoals region, south of Cape Cod, Mass. The most com- mon gravels range in diameter from 5 to 15 cm. Camera tripping-weight is visible in the upper right-hand corner. Photograph was taken at station 1103, located at lat. 41°11" N., long. 69°40 W. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION 127 A FIGURE 90.-Sand bottom containing small amounts of shell, located on the Continental Shelf northeast of Cape Charles, Va., at a depth of 48 m. Shell remains are mainly bivalve mollusks and a few echinoid tests and spines. Photograph was taken at station 1421, located at lat. 87°30 N., long. 74°44" W. N128 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES FigUrE 91.-Silty-sand bottom at a depth of 406 m on the Continental Slope east of New Jersey. In the upper left is a sodastraw worm tube (Hyalinoecia tubicola); in the lower left is the camera tripping-weight; the tips of brittlestar arms and numerous animal tracks are evident in other areas. Photograph was taken at station 1335, located at lat. 39°10' N., long. 72°30 W. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N129 FiGurE 92.-Sand bottom inhabited by a dense assemblage of sand dollars (Echinarchnius parma) at a depth of 48 m near midshelf east of Delaware. The sand dollars are 2 to 3 cm in diameter. Photograph was taken at station 1418, located at lat. 87°59' N., long. 74°29" W. ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES $ o* wel WoL a C* *s Moc +i + t % » * FIGURE 93.-Sand-shell bottom at a depth of 69 m near the Outer Continental Shelf northeast of Cape May, N. J. The star- fish is Astropecten; the shell remains are Placopecten, Arctica, and Astarte. Photograph was taken at station 1360, lo- cated at lat. 88°40'° N., long. 73°80'° W. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N181 FicurE 94.-Silty-sand bottom at a depth of 178 m on the Outer Continental Shelf near Hudson Channel, south of New York City. Dominant animals are sea anemones (Zoantharia). Bivalve shells and polychaete tubes are moderately com- mon. Photograph was taken at station 1324, located at lat. 39°20'° N., long. 72°18" W. N182 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 21.-Mean number of individuals and biomass of the macrobenthic invertebrate fauna in relation to bottom sediments for each subarea and for the entire Middle Atlantic Bight region sedtient Mean number of individuals Mean biomass type SNE NYB CHB Entire area SNE NYB CHB Entire area No./m2 N0./m2 No./m2 No./m2 g/m2 g/m2 M13 fl Gravel 2,667 - - 2,667 286 - - 286 Sand-grave1 3,157 448 311 2,089 379 94 12 256 Shell 2,925 - 1.211 1,639 117 - 706 559 Sand-shell 259 769 2,804 2,006 3 82 72 74 Sand 2.912 1.391 989 1.716 321 146 85 179 Silty-sand 1,906 1,157 1,286 105 1,725 100 414 Silt 660 464 343 486 76 72 35 59 Clay 62 105 249 165 $ 6 102 52 Unlike density, the mean biomass of all organisms in relation to sediments within the Middle Atlantic Bight region (table 21, fig. 96) did not show a con- sistent trend of decreasing quantity as particle size decreased. The largest biomass values occurred in shell, 559 g/m, and silty sand, 414 g/m". The small- est biomass values of 52, 59, and 74 g/m" were found in clay, silt, and sand-shell, respectively. Interme- diate quantities were present in gravel, sand-gravel, and sand where biomasses of 286, 256, and 179 g/m, respectively, were found. SUBAREAS SOUTHERN NEW ENGLAND The mean density of all organisms in relation to bottom sediments in the Southern New England subarea (fig. 97) showed a trend similar (a general decrease in density as particle size decreased) to that described above for the entire Middle Atlantic Bight region (fig. 95). Two exceptions are notable in this correlation with substrates. The highest den- sity was in sand-gravel, the second coarsest sediment type, where were found, and gravel, the coarsest, contained Sand-shell, ranked fourth in coarseness, contained the second lowest density of 259/m, and clay, the finest grained sub- strate, contained the lowest density, 62/m*. Densities in shell, sand, silty sand, and silt were 2,925/m, 2,912/m*;, 1,131/m', and 660/m*, respectively. Biomass in the Southern New England subarea ranged from 379 g/m in sand-gravel substrates to 3 g/m in sand-shell (fig. 98). No definite linear re- lationship between biomass and decreasing particle size was seen; although, in general, the coarser grained substrates contained larger biomasses than the finer grained. Gravel, shell, and sand sediments contained, respectively, 286, 117, and 321 g/m, whereas silty sand, silt, and clay substrates contained a biomass of 105, 77, and 5 g/m, respectively. NEW YORK BIGHT Gravel and shell substrates were not present at sampling stations in the New York Bight. The sandy substrates contained the highest densities, which in- creased as particle size decreased; the highest den- sity was found in silty-sand (1,906/m*) (fig. 97). Sand-gravel, sand-shell, and sand sediments con- tained densities of 448/m', 769/m', and 1,391/m', respectively, but silt had a density of 464/m* and clay a density of 105/m*. The mean biomass of all organisms was generally small, below 100 g/m, in most substrates. Sand- gravel contained 94 g/m; sand-shell, 82 g/m; silt, 72 g/m; and clay, 6 g/m; sand with a biomass of 146 g/m" exceeded the norm, but silty sand with 1,725 g/m" contained the largest biomass of all sedi- ment types throughout the entire study area (fig. 98). No definite correlation with sediment particle size was discernible. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N133 I I NUMBER OF INDIVIDUALS PER SQUARE METER OF BOTTOM T 2900 [- 2000 : 1500 | 1000 300 O Gravel Shell Sand I Silf F Sand - gravel Sand Silty sand Clay BOTTOM SEDIMENTS FiGurE 95.-Relation between number of individuals and bottom-sediment types. Values represent all taxonomic groups com- bined for the entire Middle Atlantic Bight region. CHESAPEAKE BIGHT Gravel was the only sediment type absent from the Chesapeake Bight subarea. The density of or- ganisms in this subarea showed a general tendency of being relatively low in both the coarsest and finest substrates (fig. 97). In the coarse sediments, sand-gravel ranked first with a density of 311/m'. Among the finer sediments, densities of 343/m> and 249/m' were found in silt and clay, respectively. Density values in the medium to moderately fine sub- strates averaged approximately 1,000 individuals per square meter; 989/m>, and 1,211/m> N134 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES S90 |- G00 - WET WEIGHT, IN GRAMS PER SQUARE METER OF BOT TOM 400 |- 200 l O Gravel Shell Sand-gravel Sand -shell Sand I Silt F Silty sand Clay BOTTOM SEDIMENTS FicurE 96.-Relation between biomass and bottom-sediment types. Values represent all taxonomic groups combined for the entire Middle Atlantic Bight region. in sand, silty sand, and shell, respectively. The high- est density of all organisms in this subarea, by a significant amount, 2,804/m', was found in sand- shell. The mean biomass of all organisms in the Chesa- peake Bight was generally lower than that in either the Southern New England or the New York Bights. However, shell and clay sediments in this subarea contained the largest recorded biomasses of the en- tire region (fig. 98). The biomass of all organisms in shell was 706 g/m? in Chesapeake Bight versus 117 g/m in Southern New England. Silty-sand and clay sediments were the only other substrates whose biomasses equalled or exceeded 100 g/m in this sub- MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N135 3157 3000 EXPLANATION 2500 |- SNE I |)! < -< & 2000 |- lll 1500 |- 1900 |- \I LIL tta NUMBER OF INDIVIDUALS PER SQUARE METER OF BOTTOM 500 |- O J Gravel I Shell Sand Silt Sand-gravel Sand- shell Silty sand Clay BOTTOM SEDIMENTS FIGURE 97.-Relation between number of individuals and bottom-sediment types. Values represent all taxonomic groups combined for each subarea. Abbreviations: SNE, Southern New England; NYB, New York Bight; CHB, Chesapeake Bight. N136 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES 25s ' 800 |- 3 o 5 700 |- EXPLANATION o > 6 == SNE o R Nuys t 600 [- LJ s LJ E S 590 O & C L & 400} & 3 s d = o S O S O # 300 |- . Z - 6 s _ K 5 = = GO ess s = W . - S = 200} = & - - E - n L = S = = § . = § 100 |- = _ o L4, = Gravel Sand Silt Sand-gravel Sand - shell Silty sand Clay BOTTOM SEDIMENTS FIGURE 98.-Relation between biomass (wet weight) and bottom-sediment types. Values represent all taxonomic groups combined for each subarea. Abbreviations: SNE, Southernern New England; NYB, New York Bight; CHB, Chesa- peake Bight. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION area. Biomasses of 85, 72, 35, and 12 g/m" were found in sand, sand-shell, silt, and sand-gravel sedi- ments, respectively. TAXONOMIC GROUPS ENTIRE MIDDLE ATLANTIC BIGHT REGION Mean densities and biomass of individual taxa, in relation to bottom sediments, for the entire Middle Atlantic Bight region are given in tables 22 and 23, and illustrated in figures 99-104. SUBAREAS The following six tables deal with each taxon's density and biomass in relation to bottom sediments in each subarea: Tables 24 and 25, Southern New England Tables 26 and 27, New York Bight Tables 28 and 29, Chesapeake Bight RELATION TO SEDIMENT ORGANIC CARBON This section contains an analysis of the relation- ships between the quantity of organic matter in bot- tom sediments, and the quantity of benthic or- ganisms. Prior to making the analysis, we considered two general cause-and-effect relationships: first, the possibility that where organic carbon was more abundant, it might provide a greater quantity of food, and thus support a larger standing crop of benthic animals; and second, the possibility (con- verse of the preceding) that where animals were more abundant, they might produce a larger amount of organic matter (fecal deposits, for example) in the sediments. In either possibility, high abundance would be associated with high carbon content. Results of the analyses, as described below, re- vealed no general correlation between sediment or- ganic carbon and the quantity of benthic animals. A few taxonomic groups showed good correlations- some direct and some inverse-between abundance and organic content, but they were the rare excep- tions. (See table 30 for the number of samples for each class of sediment organic carbon.) DISTRIBUTION OF SEDIMENT ORGANIC CARBON The geographic distribution of organic carbon in the bottom sediments of the Middle Atlantic Bight N137 region is shown in figure 105. Sediments blanketing almost the entire Continental Shelf throughout this region contained only a small amount (0.01-0.49 percent weight class) of organic carbon. Slightly larger quantities (0.5-0.99 percent) were broadly distributed in sediments on the Continental Slope and Rise, plus a moderately large area on the Outer Continental Shelf off Southern New England. Mod- erate quantities of organic carbon (1.0-1.99 percent) were widely distributed along the Continental Slope, with some incursions onto the shelf and onto the Continental Rise. The largest quantities of organic carbon (2.00-7.16 percent) were found in the bays and sounds, plus in one small area on the upper Continental Slope northeast of Cape Hatteras. Sedi- ments in some inshore waters such as Buzzards Bay, Long Island Sound, Delaware Bay, Chesapeake Bay, and Pamlico Sound also contained patches of small and moderate quantities of organic carbon. TOTAL MACROBENTHIC FAUNA OF ALL TAXONOMIC GROUPS Mean quantities of benthic animals were calculated for seven sediment organic carbon classes within each of the three subareas and for the entire Middle Atlantic Bight region. These data, for both density and biomass, are listed in table 31 and illustrated in figures 106 and 107. The values for density range from 182/m' to 5,236/m', and no trends are ap- parent. There were no correlations between density of organisms and the quantity of organic carbon in any of the subareas or for the region as a whole. Mean biomasses for the seven organic carbon classes in the various subareas and the entire region ranged from 14 g/m to 2,657 g/m. No correlations were seen between biomass and the quantity of sediment organic carbon. Because of the erratic values within carbon classes and between adjacent carbon classes in both density and biomass, we consider the trends to be spurious. TAXONOMIC GROUPS ENTIRE MIDDLE ATLANTIC BIGHT REGION The analysis in this section is based on the density and biomass of each major taxonomic group in the seven classes of sediment organic carbon from the entire Middle Atlantic Bight region. Density values are listed in table 32 and biomass values in table 33; these data are illustrated in figures 108 through 113. N138 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 22.-Mean number of individuals listed by taxonomic groups in each bottom-sediment type for the entire Middle Atlantic Bight region [In number per square meter] Bottom sediments Taxonomic group Sand- Sand- Silty Gravel gravel Shell shell Sand sand Silt Clay No./m2Z. Nom. nus ' New No./m2 _ No./m2 No./me _ No./mZ PORIFERA 5.53 4.44 - 2.25 0.19 0.26 0.46 0.28 COELENTERATA 28.33 165.17 40.00 9.00 10.45 30.70 5.11 3.50 Hydrozoa 3.67 95.17 29.25 6.02 6.40 15.47 0.03 - Anthozoa 24.66 70.00 10.75 2.98 4.05 15.23 5.08 3.50 Alcyonacea - ~ - - 0.17 1.41 1.12 0.61 Zoantharia 10.33 1.83 - 2.30 1.87 12.27 2.61 2.43 Unidentified 14.33 68.17 10.75 0.68 2.01 1.55 1.35 0.46 PLATYHELMINTHES - 13.17 - 0.36 0.29 - 0.32 - Turbellaria - 13.17 - 0.36 0.29 - 0.32 - NEMERTEA 8.00 5.50 1.50 2.52 5.39 6.67 1.57 0.61 ASCHELMINTHES 0.67 40.78 39.25 1.93 0.75 1.67 2.45 0.30 Nematoda 0.67 40.78 39.25 1.93 0.75 1.67 2.45 0.30 ANNEL I DA 289.00 389.39 362.75 174.09 412.36 272.42 90.70 27.39 POGONOPHORA ~ - - - 0.04 3.18 3.86 1.80 SIPUNCULIDA ~ 9.61 - 0.43 4.32 4.48 4.81 0.89 ECHIURA - - - - 0.01 0.50 0.32 0.30 PRIAPUL IDA - - ~ - - - 0.09 0.04 MOLLUSCA 1083.33 93.12 414.25 1448.41 198.41 478.90 270.18 96.51 Polyplacophora 2.00 4.17 - - 0.17 0.56 0.84 0.33 Gastropoda 1064.33 21.67 87.50 6.00 20.88 89.54 19.78 4.70 Bivalvia 17.00 67.28 326.75 1442.23 176.18 383.70 247.13 91.28 Scaphopoda - - - 0.18 0.79 3.20 2.43 0.20 Cephalopoda - ~ - - 0.02 1.90 - - Unidentified - - - - 0.37 - - - ARTHROPODA 361.34 1176.35 705.00 298.85 1007.93 349.33 40.94 20.95 Pycnogonida - 5.11 - 1.05 0.28 0.12 - 1.65 Arachnida - ~- ~ ~ 0.09 - - ~ Crustacea 361.34 1171.24 705.00 297.80 1007.56 349.21 40.94 19.30 Ostracoda ~ 1.17 - 0.91 0.20 - 0.09 - Cirripedia 6.67 141.28 - 0.59 22.28 84.38 0.49 - Copepoda - - - - 0.04 0.06 0.07 - Nebaliacea - - - - 0.02 - - 0.02 Cumacea - 1.56 6.25 31.73 23.84 5.74 2.35 0.46 Tanaidacea ~ ~ ~ - - 0.02 0.28 0.26 Isopoda - 5.78 6.25 10.68 16.86 11.09 7.00 0.11 Amphipoda 272.00 1008.67 266.25 238.57 933.33 240.55 30.33 18.41 Mysidacea - 0.11 - 3.93 2.83 1.86 - - Decapoda 82.67 12.67 50.25 11.39 8.16 5.51 0.33 0.04 BRYOZOA 3.00 163.56 376.00 24.34 3.78 29.04 ~ - BRACHIOPODA - - - - 0.01 - ~ - ECHINODERMATA ~ 1.45 6.25 32.34 56.90 114.49 30.97 3.71 Holothuroidea ~ 0.17 ~ 0.36 1.38 7.81 1.23 0.22 Echinoidea - - - 30.07 40.85 0.24 0.10 0.04 Ophiuroidea - 1.28 6.25 1.52 13.53 105.62 28.84 3.41 Asteroidea - - - 0.39 1.14 1.12 0.80 0.04 HEMICHORDATA - ~ - - 0.14 0.33 0.07 - CHORDATA 885.33 17.56 68.75 5.70 10.90 13.67 3.85 2.54 Ascidiacea 885.33 17.56 68.75 5.70 10.90 13.67 3.85 2.54 UNIDENTIFIED 2. 33 8.56 1.50 6.16 6.12 6.83 15.67 5.72 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N139 TABLE 23.-Mean biomass of each taxonomic group listed by bottom-sediment type for the entire Middle Atlantic Bight region [In grams per square meter] Bottom sediments Taxonomic group Gravel Sand-gravel Shell Sand-shell Sand Silty sand Silt Clay g/m g/m? g/m? g/m g/m? g/m? g/m? g/m? PORIFERA 0.210 0.886 = 0.245 0.011 0.010 0.002 0.030 COELENTERATA 18.600 6.382 1.550 6.930 1.003 7.052 1.977 1.954 Hydrozoa 1.153 2.767 0.788 0.634 0.263 0.085 <0. 001 - Anthozoa 17.467 3.615 0.762 6.297 0.740 6.966 1.977 1.954 Alcyonacea =- - - - 0.023 0.107 0.146 0.115 Zoantharia 17.047 2.140 - 6.233 0.619 6.702 1.746 1.626 Unidentified 0.420 1.475 0.762 0.063 0.098 0.158 0.086 9.213 PLATYHELMINTHES - 0.071 - 0.007 0.008 - 0.002 - Turbellaria - 0.071 - 0.007 0.008 - 0.002 ~ NEMERTEA 5.813 0.739 0.110 0.355 0.714 0.694 0.474 0.006 ASCHELMINTHES 0.007 0.011 0.072 0.009 0.002 0.004 0.009 0.003 Nematoda 0.007 0.011 0.072 0.009 0.002 0.004 0.009 0.003 ANNEL IDA 24.283 8.709 27.802 8.591 14.117 26.146 6.744 2.436 POGONOPHORA - - - - <0. 001 0.024 0.059 0.007 SIPUNCUL IDA - 1.589 - 0.033 0.560 1.094 1.292 0.142 ECHIURA - - - - 0.006 0.308 1.154 0.648 PRIAPULIDA - - - - - - 0.058 0.022 MOLLUSCA 16.953 156.634 387.138 37.523 121.066 343.231 25.886 43.874 Polyplacophora 0.227 4.292 - - 0.004 0.010 0.009 0.005 Gastropoda 11.487 2.424 1.062 2.195 3.114 6.856 0.331 0.0193 Bivalvia 5.240 149.919 386.075 35.327 117.933 336.270 25.513 43.848 Scaphopoda - = = 0.001 0.012 0.068 0.033 0.002 Cephalopoda - - - - <0.001 0.026 - - Unidentified - - = - 0.002 - - - ARTHROPODA 14.573 73.624 33.640 6.019 10.010 5.865 0.277 0.126 Pycnogonida - 0.022 - 0.006 0.001 0.002 - 0.011 Arachnida - - - - <0. 001 - - - Crustacea 14.573 73.602 33.640 6.013 10.008 5.863 0.277 0.115 Ostracoda - 0.012 - 0.007 0.002 - 0.001 2 Cirripedia 0.143 61.358 - 0.003 2.872 1.969 0.015 - Copepoda - - - - <0. 001 «0.001 0.001 - Nebaliacea - - - - <0. 001 - - <0. 001 Cumacea - 0.016 0.015 0.089 0.111 0.029 0.016 0.008 Tanaidacea - - - - - <0.001 0.002 0.002 Isopoda - 0.239 0.062 0.433 0.448 0.089 0.057 0.001 Amphipoda 0.600 4.649 1.032 2.052 5.768 2.464 0.149 0.081 Mysidacea - 0.001 - 0.021 0.010 0.015 - - Decapoda 13.830 7.328 19.520 2.894 0.646 1.244 0.036 0.022 BRYOZOA 1.187 3.236 13.010 0.514 0.154 0.051 - - BRACHIOPODA - - - - <0. 001 - - - ECHINODERMATA - 0.974 0.125 13.563 29.792 25.147 5.687 1.449 Holothuroidea - 0.163 - 0.352 2.393 14.665 0.158 0.927 Echinoidea - - - 12.632 24.411 1.171 0.799 0.040 Ophiuroidea - 0.811 0.125 0.044 1.187 5.425 1.816 0.480 Asteroidea - - = 0.535 1.780 3.886 2.914 0.001 HEMICHORDATA - - - - 0.022 0.105 0.001 - CHORDATA 204.080 1.627 108.645 0.479 1.890 3.922 0.826 0.725 Ascidiacea 204. 080 1.627 108.645 0.479 1.890 3.922 0.826 0.725 UNIDENTIFIED 0. 350 1.3573 0.020 0.589 0.138 0.362 0.241 0.269 N140 PER. SQUARE MEIER OF BOT FOM SPECIMENS OF N U M B E R Figure 99.-Density (No.) and biomass (wt.) in relation to bottom sediments in the entire Middle Atlantic Bight 100 80 60 40 20 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES PORIFERA (k __| < HLR ALCYONARIA prea ags " 0.4 710.2 428 412.0 0.14 0.12 8 0.10 0.08 0.06 0.04 0.02 BOTTOM SEDIMENTS ZOANTHARIA 120 PLATYHELMINTHES ... -10,.08 0.06 0.04 <10.02 NEMERTEA region for Porifera, Hydrozoa, Alcyonaria, Zoantharia, Platyhelminthes, and Nemertea. [N. GRAMS "PER SQUARC METER - OF -_BOTTOM WwET WEIGHT, MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION NI141 sek mr" NEMATOBA --== [o m------- SIPUNCULA I No. S Wt. = 0 & 3 E 0 O i- a i- (o kz c 0 LL o 0 LJ - [Gat LJ LJ = ANNEHIDA-+-#= w LJ soof 3sp rok ECHIURA s LL] _-_ o = 5 y a 02 3 [== {5 < 2 3) s ig 0 0 0 & LJ O- ema POGONOPH e z I 10 f- ORA uy 40.06 0.10 e S i- LL E z- O = <4 (G] 8|- = 0.08 0.08 h o 5 3 3 40.04 - c 6}- & 0.06 0.06 p- 3 LJ 003 I 3 < 0.04 10.04 0.02 001 002 0.02 C 3 ® $ BOTTOM SEDIMENTS FigUrE 100.-Density (No.) and biomass (wt.) in relation to bottom sediments in the entire Middle Atlantic Bight region for Nematoda, Annelida, Pogonophora, Sipuncula, Echiura, and Priapulida. N142 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES POLYPLACOPHORA ----4 | SCAPH 5 s 5 «Faes OPODA a_ N No. 4L- SWL 44 0.08 > 9 e 0.06 > oo 0 O - m 0.04 i- $ LL C £ 0.02 & 5 o LJ fe o C s i- m ----- GASTROPODA u ¢ 3s (of CEPHALOPODA gos # & i400 S y <4 = 410 o 3 1200r °= 8|- 410.04 er (e) & > w 1000} G2 O sn. 6|- 410.03 & C - & eee y 800 g 1:6 E S a eocl < 4 |- = 10.02 a. Es 4 C & § = ( 400 = 5 P 2r s M [efel] be < o o o o L204 1 1 _ sube 1 1 o O LJ p BIVALVIA PYCNOGONIDA h 4 ve I1 O- ~1Go25 R 4s 1400} = § 0 S o = w 1200}- =" S 8} = 10.020 & e S S -|300 S ys u 1000} = = s * c = E 6|- = <10.015 's S 8o0o|- s = 5 S Lu 2 - _ 200 § = z eoo}|- S 4 = 0.010 400}|- _ 1100 E 2 = 0.005 200}|- 5 0 0 0 0 MX Ny 8 ~A 's (P> yar 8 O a a SHAH a".s o LS rE OSA & ZF eR 3 2 * o F# * PP P ¥ o" ¢ 'if ¥ ¢ "£ BOTTOM SEDIMENTS FIGURE 101.-Density (No.) and biomass (wt.) in relation to bottom sediments in the entire Middle Atlantic Bight region for Polyplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda, and Pyenogonida. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N143 OSTRACODA |------ ------NEBALIIACEA : -----71 2.0} |- onct 0.0005 M No. - 3 s Wi, - 40012 o08|- S 40.0004 C 0.010 5 0 oo6|- & Jocoos ., F 0.008 = 0 © 3 a. 7 0.006 o.04}|- jo 0002 £ L. 0.004 = C O 0.02|- > ~[0OO9O1 _ ic i 0.002 E - & live o oE _- {__ isi $5 1 o & t a 3 _-~-_-_x__ L oot CIRRIPEDIA a sof CUMACEA % LJ g -| 0.14 ig < t 2 150 9.12 aq 0 D i 0.10 O & & 100 0.08 o LJ LJ f 0.06 a. (#) & 50 2 0.04 C 5 0.02 2 he o o S LJ e COPEPODA TANA £ w o.10|- 10.0010 0.5}- NAIDACEA 10.005 ps LL bent O GO o.08}|- 10.0008 o4|- 10.004 J oC to 3 m o.06|- -0.0006 o3|- 10.003 * ps LJ 3 3 £ 0.04}|- -10.0004 0.002 00 2}- |0.0002 0001 o _ [L. __} | o 0 V) VJ % V) $p / CSREES & .f .P ## + FF 7 7 / o" 45> f ¥ 09V 5 BOTTOM SEDIMENTS FIGURE 102.-Density (No.) and biomass (wt.) in relation to bottom sediments in the entire Middle Atlantic Bight region for Ostracoda, Cirripedia, Copepoda, Nebaliacea, Cumacea, and Tanaidacea. N144 SQUARE METER OF. BOTTOM PCR SPECIMENS NUMBER _ OF Figure 103.-Density (No.) and biomass (wt.) in relation to bottom sediments in the entire Middle 20 1400 |- 1200 1000 800 600 400 200 ATLANTIC CONTINENTAL ® o I o F W No. Wt. EEE T EET IIL AMPHIPODA MYSIDACEA L WLL s'y 19 2 g ! # ¥ < 0.5 0.2 - 0.025 0.020 0.0 15 0.010 0.005 SHELF AND SLOPE OF THE UNITED 80 - 60 40 - 20 |- 500 400 300 200 100 DECAPODA IATL EEET EEE EEE EEE EEE EEET Eee EE EEE EEE IEEE BRYOZOA STATES BRACHIOPODA ---- 420 IN- GRAMS PER SQUARE METER ~OF BOTTOM 0.10|- 0.0005 e I C& 0.08 |- -100004 <- L = 0.06 |- -0.0003 p LJ = < 0.0002 0.02|- -10.0001 0 \ L... § F fcc 0 pi FFF SL F P .9 § ¢ ® ig. 3 BOTTOM SEDIMENTS region for Isopoda, Amphipoda, Mysidacea, Decapoda, Bryozoa, and Brachiopoda. Atlantic Bight MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N145 r---- HOLOTHUROIDEA ---- r----«- ASTEROIDEA -| 5 nat pat = i.o|- C < [ o.8|- a O i- c 0.6- -- 0 LL c o4a|- 0 14 & 0.2} & yL-l—J 0 1 | C 2 a 3 L sf ECHINOIDEA $% ost 2 LJ CC L OPHIUROIDE ASCIDIACEA { $ A 16 1000}|- E ii. p = = {200 x O = 45 $ 120|- > soo|- o - LJ CC == L ioo 41150 3 m e0o}|- p 3 so os s p = [Kele) > z 60 400 = 40 = 200 = 50 20 = o o o yE ~ M ols a CSAC A .P .9 «& & ¥ # 4%" cydoy " y 0 8° s» xo 4"; $ ¥ ( BOTTOM SEDIMENTS FIGURE 104.-Density (No.) and biomass (wt.) in relation to bottom sediments in the entire Middle Atlantic Bight region for Holothuroidea, Echinoidea, Ophiuroidea, Asteroidea, Hemichordata, and Ascidiacea. N146 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 24.-Mean number of individuals listed by taxonomic group in each bottom-sediment type for the Southern New England subarea [In number per square meter] Bottom sediments Taxonomic group € Sand- Sand- Silty Gravel gravel Shell shell Sand sand Silt Clay No./me _ No./m2 _ No./mZ No. /me. No./m2 _ No./m2 No./m2 _ No./m2 PORIFERA 5.35 Jw27 - - 0.39 0.17 - 0.20 COELENTERATA 26.33 256.91 - - 18.38 15.29 7.44 2.40 Hydrozoa 3.67 144.09 - ~ 13.23 0.12 - - Anthozoa 24.66 122.82 - - $.15 15.17 7.44 2.40 Alcyonacea - ~- - - 0.13 1.50 2.08 0.70 Zoantharia 10.33 1.27 - - 4.29 12.63 4.56 0.20 Unidentified 14.33 111.55 - - 0.73 1.04 0.80 1.50 PLATYHELMINTHES - 21.56 - - 0.40 - 0.04 - Turbellaria - 21.56 - - 0.40 - 0.04 - NEMERTEA 8.00 6.91 - 4.00 7.94 5,56 2.52 - ASCHELMINTHES 0.67 66.73 ~ - 2:29 2.65 2:20 0.80 Nematoda 0.67 66.73 - - 2.29 2.66 2.20 0.80 ANNEL IDA 289.00 555.18 750.00 23.00 433.31 330.82 118.52 9.10 POGONOPHORA - - - - 0.05 1.33 5.36 3.00 SIPUNCULIDA - 15.73 - l 11.20 7.06 10.12 0.90 ECHIURA - - - - - 0.04 0.24 0.80 PRIAPULIDA - - ~ - - ~- 0.24 - MOLLUSCA 1083.33 145.10 375.00 76.00 126.94 222.47 336.44 21.10 Polyplacophora 2.00 6.82 - - 0.37 0.98 1.32 0.20 Gastropoda 1064.33 33.64 275.00 65.00 19.23 34.19 4.40 0.60 Bivalvia 17.00 104.64 100.00 11.00 105.51 182.73 328.00 20.30 Scaphopoda - - - - 0.49 1:13 272 - Cephalopoda - - - - 0.06 3.44 - - Unidentified - - - - 1.28 - - - ARTHROPODA 361.34 1770.35 300.00 154.00 2228.16 326.63 54.60 3.80 Pycnogonida = 8.36 - - - - ha - Arachnida - - - - - - - - Crustacea 361.34 1761.99 300.00 154.00 2228.16 326.63 54.60 3.80 Ostracoda - 1.91 - - 0.47 - - - Cirripedia 6.67 231.18 - ~ 15. 22 - - - Copepoda = - - - 0.07 0.12 0.20 - Nebaliacea - - - - - - - - Cumacea ~ 2.36 - - 57.65 8.27 5.64 1.20 Tanaidacea - - - - f 0.04 0.44 0.80 Isopoda - 4.36 25.00 - 19.05 2.58 0.96 0.30 Amphipoda 272.00 1508.18 225.00 154.00 2125.11 309.40 47.36 1.50 Mysidacea - - - - 0.89 3.37 - - Decapoda 82.67 14.00 50.00 - 9.70 2.85 - - BRYOZOA 3.00 267.45 1500.00 - 5.59 0.17 - - BRACKHIOPODA - - ~ - ~ - - - ECHINODERMATA - 0.28 - - 58.59 187.35 81.28 8.20 Holothuroidea - ~ - - 3.83 9.69 3.00 0.20 Echinoidea - - - - 22.01 0.37 0.28 0.20 Ophiuroidea - 0.28 - - 30.11 175.85 76.28 7.80 Asteroidea - ~ - - 2.64 1.44 1:72 - HEMICHORDATA - ~ - - 0.31 0.38 0.20 - CHORDATA 885.33 28.45 - 2.00 18.98 7.20 3.50 Ascidiacea 885.33 28.45 - 2.00 18.98 23.37 7.20 3.50 UNIDENTIFIED 2.3% 13.73 - - 7.93 8.10 6.88 8.30 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N147 TABLE 25.-Mean biomass of each taxonomic group listed by bottom-sediment type for the Southern New England subarea [In grams per square meter] Taxonomic group Bottom sediments Gravel Sand-gravel Shell Sand-she1l Sand Silty sand Silt Clay a/m2 g/m2 g/m2 g/m g/m2 g/m? ww" _ g/s" PORIFERA 0.210 1.450 - 0.036 0.003 = $.127 COELENTERATA 18.600 9.225 - - 1.470 9.294 2.576 0.928 Hydrozoa 1.133 4.019 - - 0.796 0.047 - - Anthozoa 17.467 5.206 - - 0.674 9.247 2.576 0.928 Alcyonacea - - - - 0.003 0.047 0.168 0.129 Zoantharia 17.047 2.793 - - 0.586 9.075 2.367 0.163 Unidentified 0.420 2.414 - - 0.085 0.125 0.041 0.636 PLATYHELMINTHES - 0.116 - - 0.012 - <0. 001 - Turbellaria = 0.116 = - 0.012 - <0. 001 - NEMERTEA 5.813 1.111 - 0.020 0.887 0.750 0.119 - ASCHELMINTHES 0.007 0.018 - - 0.005 0.006 0.010 0.008 Nematoda 0.007 0.018 - - 0.005 0.006 0.010 0.008 ANNEL IDA 24.283 11.169 30.500 1.670 21.470 25.835 7.427 0.445 POGONOPHORA - - - - <0. 001 0.023 0.017 0.012 SIPUNCUL IDA - 2.600 - - 1.256 1.761 0.958 0.628 ECHIURA - - - - - 0.001 0.093 0.709 PRIAPUL IDA - - - - B - 0.159 - MOLLUSCA 16.953 223.297 4.250 0.430 252;317 22.494 10.734 0.525 Polyplacophora 0.227 7.023 - - 0.003 0.018 0.016 0.002 Gastropoda 11.487 3.917 3.750 0.370 6.302 0.793 0.104 0.029 Bivalvia 5.240 212.357 0.500 0.060 245.996 21.622 10.664 0.494 Scaphopoda - - - - 0.009 0.014 0.039 - Cephalopoda - - - - 0.001 0.047 - - Unidentified - - - - 0.005 - - - ARTHROPODA 14.573 113.338 30.500 0.630 17.579 2.761 0.380 0.049 Pycnogonida - 0.036 - - - - - - Arachnida - - - - - - - - Crustacea 14.573 113.303 30.500 0.630 17.579 2.761 0. 380 0.049 Ostracoda - 0.019 - - 0.003 - - - Cirripedia 0.143 100.404 - - 3-136 - - - Copepoda - - - - <0. 001 0.001 0.002 - Nebaliacea - - - - - - - - Cumacea - 0.024 - - 0.260 0.037 0.037 0.030 Tanaidacea - - - - - <0. 001 0.004 0.006 Isopoda - 0.357 0.250 - 0.392 0.171 0.010 0.001 Amphipoda 0.600 6.501 1.750 0.630 13.252 2.354 0.327 0.012 Mysidacea - - - - 0.002 0.027 - - Decapoda 13.830 5.998 28.500 - 0.533 0.171 - - BRYOZOA 1.187 5.293 52.000 - 0.364 0.001 - - BRACHIOPODA - - - - - - - - ECHINODERMATA - 1.326 - - 23.924 35.282 49.234 0.756 Holothuroidea - - - - 7.238 21.704 35.195 0.174 Echinoidea - - - - 12.642 1.605 2.206 0.185 Ophiuroidea - 1.326 - - 3.215 9.134 3.896 0.397 Asteroidea - - - - 0.829 2.840 7.937 - HEMI CHORDATA - - - - 0.062 0.080 0.002 - CHORDATA 204.080 2.646 - 0.170 1.894 6.313 2.054 0.542 Ascidiacea 204.080 2.646 - 0.170 1.894 6.313 2.054 0.542 UNIDENTIFIED 0.350 2.228 - - 0.334 0.344 0.424 0.094 N148 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 26.-Mean number of individuals listed by taxonomic group in each bottom-sediment type for the New York Bight subarea [In number per square meter] Bottom sediments Taxonomic group Sand- Sand- Silty Gravel gravel Shell shell Sand sand Silt Clay No./me _ No./me _ No./mZ No. /mZ No./m2 _ No./m2 _ No./m2 PORIFERA - - - 4.31 0.15 0.72 - - COELENTERATA - 6.40 - 9.01 3.53 50.17 4.89 1.78 Hydrozoa - 2.60 ~ 8.63 2.07 23.89 0.13 - Anthozoa - 3.80 - 0.38 1.46 26.28 4.76 1.78 Alcyonacea - - - - 0.32 2.94 0.50 1.21 Zoantharia - 3.80 - 0.38 0.53 23.72 4.13 0.14 Unidentified - - - - 0.61 2.56 0.13 0.43 PLATYHELMINTHES - I T 0.25 0.07 - - - Turbellaria - - - 0.25 0.07 - - - NEMERTEA - 4.00 - 3.31 3:03 2.28 1.38 0.14 ASCHELMINTHES - - - - 0.07 0.50 0.50 - Nematoda ~ - - - 0.07 0.50 0.50 - ANNEL IDA ~ 142.40 - 224.25 532.79 285.39 48.69 11.29 POGONOPHORA - - - - 0.02 2.89 4.69 2.07 SIPUNCULIDA - ~ - 0.56 2.46 1.89 1.88 0.79 ECHIURA - - - - - 1.33 0.38 0.29 PRIAPULIDA ~ - - - - - - - MOLLUSCA - 4.60 - 127.50 141.52 837.97 378.38 74.72 Polyplacophora - - - - 0.05 - 0.13 0.29 Gastropoda - 0.40 - 8.25 25.66 39.17 13.44 2.43 Bivalvia ~ 4.20 ~ 119.25 114.54 793. 33 362.50 71.36 Scaphopoda - - - - 1.27 5.67 2.31 0.64 Cephalopoda - - - - - - - - Unidentified - - - - - - - - ARTHROPODA - 289.80 - 330.38 620.04 700.27 15.45 2.14 Pycnogonida =- - - - - 0.61 - - Arachnida - - - - 0.22 - - - Crustacea - 289.80 - 330.38 619.82 699.66 15.45 2.14 Ostracoda - - - 2.50 0.11 = h > Cirripedia - - - ~ 43.03 440.67 2.12 ~ Copepoda ~- - - - 0.03 - - - Nebaliacea - - - - - - - 0.14 Cumacea - 0.40 - 10.31 11.80 1.67 0.38 0.64 Tanaidacea - - - - - - - 0.29 Isopoda - 8.60 - 11.00 12.25 12.28 5.69 0.14 Amphipoda - 267.60 - 286.44 541.72 2353.33 6.56 0.79 Mysidacea - 0.40 - 2.14 1.07 - - - Decapoda - 12.80 - 17.00 9.81 11.71 0.69 0.14 BRYOZOA - 0.40 - 18.56 3.90 9.06 - - BRACHIOPODA - - - ~ - - - - ECHINODERMATA - - - 23.70 78.02 9.61 1.95 3.64 Holothuroidea - - - 0.63 0.50 4.44 0.38 0.43 Echinoidea - - - 21.38 60.83 0.22 - - Ophiuroidea - - =- 0.75 10.94 3.39 1.44 3.21 Asteroidea - - - 0.94 0.75 1.56 0.13 - HEMICHORDATA - ~ - - 0.11 - - - CHORDATA - 0.60 - 15.56 5.62 0.22 3.94 2.43 Ascidiacea - 0.60 - 15.56 5.62 0.22 3.94 2.43 UNIDENTIFIED = i = 11.69 4.97 0. 94 1.94 5.50 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N149 TABLE 27.-Mean biomass of each taxonomic group listed by bottom-sediment type for the New York Bight subarea [In grams per square meter] Taxonomic group Bottom sediments Gravel Sand-gravel Shell Sand-shell Sand Silty sand Silt Clay g/m? g/m2 g/m g/m? g/m g/m? g/m? _ g/m? PORIFERA - - - 0.292 0.002 0.007 - - COELENTERATA - 1.596 - 0.476 0.778 4.605 3.908 0.452 Hydrozoa - 0.036 - 0.046 0.055 0.253 0.001 - Anthozoa - 1.560 - 0.430 0.722 4.352 3.906 0.452 Alcyonacea - - - - 0.054 0. 226 0.039 0.058 Zoantharia - 1.560 - 0.430 0.609 3.784 3.830 0.149 Unidentified - - - - 0.059 0. 342 0.038 0.245 PLATYHELMINTHES - - - 0.005 0.004 - - - Turbellaria - - - 0.005 0.004 - - - NEMERTEA - 0.212 - 0.358 0.814 0.562 1.594 0.001 ASCHELMINTHES - - - - <0. 001 0.001 0.005 - Nematoda - - - - <0. 001 0.001 0.005 - ANNEL IDA - 4.126 - 9.349 12.187 42.360 6.749 1.839 POGONOPHORA - - - - <0. 001 0.017 0.024 0.009 SIPUNCULIDA - - - 0.020 0.456 0.216 0.153 0.009 ECHIURA - - - - - 1.327 1.676 0.142 PRIAPUL IDA - - - - - - - - MOLLUSCA - 72.496 - 50.451 78.800 1640.064 55.188 0.880 Polyplacophora - - - - <0. 001 - 0.001 0.009 Gastropoda - 0.092 - 3.828 1.786 8.334 1.069 0.018 Bivalvia - 72.404 - 46.623 76.994 1631.601 54.088 0.846 Scaphopoda - - - - 0.020 0.128 0.029 0.006 Cephalopoda - - - - - - - - Unidentified - - - - - - - - ARTHROPODA - 15.284 - 9.858 8.771 19.821 0.209 0.091 Pycnogonida - - - - - 0.012 - - Arachnida - - - - 0.001 - - - Crustacea - 15.284 - 9.858 8.770 19.808 0.209 0.091 Ostracoda - - - 0.020 0.001 - - - Cirripedia - - - - 4.728 10.283 0.064 - Copepoda - - - - <0. 001 - - - Nebaliacea - - - - - - - 0.001 Cumacea - 0.004 - 0.036 0.062 0.017 0.004 0.006 Tanaidacea - - - - - - - 0.003 Isopoda - 0.054 - 0.481 0.480 0.074 0.042 0.001 Amphipoda - 2.090 - 2.209 2.765 5.758 0.028 0.008 Mysidacea - 0.004 - 0.016 0.006 - - - Decapoda - 13.132 7.097 0.726 3.677 0.071 0.071 BRYOZOA - 0.004 - 0.308 0.096 0.164 - - BRACHIOPODA - - - - - - - - ECHINODERMATA - - - 8.437 44.257 101.885 2.436 2.096 Holothuroidea - - - 0.054 0.335 0.427 1.560 1.634 Echinoidea - - - 7.184 39.688 1.479 - - Ophiuroidea - - - 0.008 0.587 87.889 0.721 0.463 Asteroidea - - - 1.191 3.648 12.090 0.155 - HEMICHORDATA - - - - 0.009 - - - CHORDATA - 0.036 - 1.307 0.264 0.029 0.273 0.462 Ascidiacea = 0.036 £ 1.307 0.264 0.029 0.273 0.462 UNIDENTIFIED - - - 1.567 0.066 0.668 0.018 0.047 N150 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 28.-Mean number of individuals listed by taxonomic group in each bottom-sediment type for the Chesapeake Bight subarea [In number per square meter] Bottom sediments Taxonomic group Sand- Sand- Silty Gravel gravel Shell shell Sand sand Silt Clay No./m2 _ No./m2 _ No./mZ _ Nous - nels No./m2 _ No./m2 PORIFERA - - - 1.11 0.05 0.08 11.11 0.50 COELENTERATA - 57.50 53.33 9.33 8.13 47.30 3.15 5.09 Hydrozoa - 57.50 39.00 4.70 1.91 42.42 - - Anthozoa - - 14.33 4.63 6.62 4.88 3.15 5.09 Alcyonacea - - - - - 0.08 0.61 0.18 Zoantharia - - - 3:52 1.38 2.88 - 4.91 Unidentified - - 14.33 1.11 5.24 1.92 2.54 - PLATYHELMINTHES - - - 0.44 0.50 - 0.75 - Turbellaria - - - 0.44 0.50 - 0.75 - NEMERTEA - 1.50 2.00 2.00 6.17 12.38 0.82 1.18 ASCHELMINTHES - - 52.33 3.15 0.18 0.42 1.32 0.32 Nematoda - - $2.33 3.15 0.18 0.42 1:32 0.32 ANNEL IDA - 95.00 233.67 149.96 222.50 136.38 89.86 45.95 POGONOPHORA - - - - 0.07 7.42 16.93 1.09 SIPUNCUL IDA =- i - 0.37 0.14 0.83 1.75 0.95 ECHIURA - - - - 0.02 0.88 0.36 0.09 PRIAPUL IDA - - - - - - - 0.09 MOLLUSCA - 28.50 427.33 2282.00 348.92 764.78 149.21 144.64 Polyplacophora - - - - 0.13 0.08 0.82 0.41 Gastropoda - 9.00 25.00 2.48 15.81 247.25 37.14 8.00 Bivalvia - 19.50 402.33 2279.22 332.58 $11.92 109.00 136.23 Scaphopoda =- - - 0.30 0.40 5.83 2.25 - Cephalopoda - - - - = - - - Unidentified - - - - - - - - ARTHROPODA - 125.50 338.66 285.51 347.06 135.38 43.32 40.77 Pycnogonida - - - 1.70 0.94 - - 3.45 Arachnida - - - - ~ - - - Crustacea - 125.50 338.66 283.81 346.12 135.38 43.32 37.32 Ostracoda - - - - 0.05 - 0.21 - Cirripedia - - - 0.96 0.11 - - - Copepoda - - - - - - - - Nebaliacea - - - - 0.07 - - - Cumacea - - 8.33 45.59 733 3.33 0.54 - Tanaidacea - - - - - - 0.29 - Isopoda - 6.50 - 10.89 21.17 28.63 13.14 - Amphipoda - 114.00 280.00 213.33 305.83 96.79 28.71 37/32 Mysidacea - - - 4.56 - - - Decapoda - 5.00 50.33 8.48 4.33 6.63 0.43 - BRYOZOA - - 153 28.67 1.86 4.21 - - BRACHIOPODA - - - - 0.02 - - - ECHINODERMATA - 1.80 $.33 38.66 32.54 35.29 2.64 1:73 Holothuroidea - 1.50 - 0.22 0.18 5.08 0.14 0.09 Echinoidea - - - 36.33 31.39 - - - Ophiuroidea - - 8.33 2.04 0.77 30.13 2.14 1.55 Asteroidea ~ - - 0.07 0.20 0.08 0.36 0.09 HEMICHORDATA - - - - - 0.46 - - CHORDATA - - 0.92 - 10.33 2.175 0.82 2.18 Ascidiacea - - 0.92 - 10.33 2.75 0.82 2.18 UNIDENTIFIED = 1.50 2.00 3.11 6.52 8.50 31.36 4.68 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N151 TABLE 29.-Mean biomass of each taxonomic group listed by bottom-sediment type in the Chesapeake Bight subarea [In grams per square meter] Taxonomic group Bottom sediments Gravel Sand-gravel Shell Sand-shel1 Sand Silty sand Silt Clay g/m? g/m2 g/m? g/m2 g/m? g/m? g/m __ g/m? PORIFERA - - - 0.226 0.001 0.026 0.004 0.005 COELENTERATA - 2.710 2.067 10. 988 0.858 3.883 0. 340 3.376 Hydrozoa - 2.710 1.050 0. 982 0.028 0.042 - - Anthozoa - - 1.017 10.006 0.830 3.841 0.340 3.375 Alcyonacea - - - - - 0.004 0.187 0.144 Zoantharia - - - 9.903 0-665 3.747 - 3.231 Unidentified - - 1.017 0.103 0.165 0.090 0.153 - PLATYHELMINTHES - - - 0.009 0.011 - 0.004 - Turbellaria - - - 0.009 0.011 - 0.004 - NEMERTEA - 0.015 0.147 0.366 0.404 0.672 0.151 0.012 ASCHELMINTHES - - 0.097 0.015 0.001 0.002 0.011 0.002 Nematoda - - 0.097 0.015 0.001 0.002 0.011 0.002 ANNEL IDA - 6.640 26.903 8.398 9.562 14.659 6.131 3.722 POGONOPHORA - - - - <0. 001 0.031 0.117 0.004 SIPUNCUL IDA - - - 0.042 0.016 0.308 2.241 0.006 ECHIURA - - - - 0.022 0.210 1.804 0.941 PRIAPULIDA - - - - - - - 0.046 MOLLUSCA - 0.335 514.767 31.236 50.749 65.537 22.591 90.937 Polyplacophora - - - - 0.011 0.001 0.007 0.004 Gastropoda - 0.040 0.167 1.295 1.830 18.885 0.111 0.015 Bivalvia - 0.295 514.600 29.939 48.903 46.511 22.444 - 90.918 Scaphopoda - - - 0. 002 0.005 0.141 0.030 - Cephalopoda - - - - - - - - Unidentified - - - - - - - - ARTHROPODA - 1.040 17.340 3.106 3.755 2.143 0.225 0.183 Pycnogonida = = - 0.009 0.005 - = 0.024 Arachnida - - - - - - - - Crustacea - 1.040 17.340 3.097 3.751 2.143 0.225 0.160 Ostracoda - - - - <0. 001 - 0.001 - Cirripedia - - - 0.005 0.004 - - - Copepoda - - - - - - - - Nebaliacea - - - - <0. 001 - - - Cumacea - - 0.020 0.124 0.031 0.021 0.005 - Tanaidacea - - - - - - 0.001 - Isopoda - 0.050 - 0.422 0.457 0.146 0.107 - Amphipoda - 0.860 0.793 2.011 2.589 0.231 0.060 0.160 Mysidacea - - - 0.026 0.022 - - - Decapoda - 0.130 16.527 0.510 0.646 1.745 0.050 - BRYOZOA - - 0.013 0.655 0.027 0.075 - - BRACHIOPODA - - - - <0. 001 - - - ECHINODERMATA ~ 1.470 0.167 17.104 15.197 10.890 0.806 1.352 Holothuroidea - 1.470 - 0.543 0.498 10.092 0.217 0.820 Echinoidea - - - 16.328 14.579 - - - Ophiuroidea - 0.167 0.067 0.025 0.796 0.583 0.529 Asteroidea - - - 0.166 0.096 0.002 0.005 0.002 HEMI CHORDATA - - - - - 0.240 - - CHORDATA - - 144.867 - 4.170 1.662 0.047 0.976 Ascidiacea - - 144.867 - 4.170 1.662 0.047 0.976 UNIDENTIFIED - 0.100 0.027 0.032 0.046 0.172 0.204 0.490 N152 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES SEDIMENT ORGANIC CARBON Percent weight 0.01 - 0.49 0.50 - 0.99 100 - 1.99 200-716 FIGURE 105.-Geographic distribution of organic carbon in the bottom sediments of the Middle Atlantic Bight region. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N153 6000 | I I I I I EXPLANATION SNE __ x----x x 5000 |- NYB A--A / M CHB - G6 ENTIRE 4000 |- AREA @«---@ 3000 |- 2000 I NUMBER OF INDIVIDUALS PER SQUARE METER OF BOTTOM 1000 |- 0 0.01 0.5 1.0 1.5 2 0 3.0 5.0 7.0 ORGANIC CARBON, IN PERCENT WEIGHT FIGURE 106.-Relation between number of individuals and sediment organic carbon. Values represent all taxonomic groups combined for each subarea and for the entire Middle Atlantic Bight region, Abbreviations: SNE, Southern New England; NYB, New York Bight; CHB, Chesapeake Bight. N154 Neither the density nor the biomass values corre- lated in a general way with the amount of sediment organic carbon. Most of the taxonomic groups showed erratic trends in both density and biomass in relation to carbon. However, a few individual groups revealed good correlations. The groups that showed a direct relation between density (table 32) and car- bon were Porifera (fig. 108), Pyenogonida (fig. 110), and Copepoda (fig. 111); Nematoda (fig. 109) re- vealed an inverse relation. Cirripedia (fig. 111) showed a direct relation between biomass (table 38) and carbon, and Cumacea (fig. 111) and Echinoidea (fig. 113) showed an inverse relation. Where quan- titative relationships between higher taxa (such as phyla, classes, and orders) from a broad geograph- ical area and sediment organic carbon are eval- uated, little evidence of interdependence is seen. sOUTHERN NEW ENGLAND The analysis in this section is based on the density and biomass of each major taxonomic group in the seven classes of sediment organic carbon for a much smaller geographic area. Density values are listed in table 34, and biomass values are listed in table 35. The range of values and their fluctuations resemble those described (tables 32 and 33) for the entire Middle Atlantic Bight region. In one group (Cope- poda), a direct correlation between quantity of or- ganic carbon and density was seen, and in two groups (Sipunculida and Amphipoda), an inverse relationship was seen. In the vast majority of taxo- nomic groups, however, the quantity of animals varied in irregular patterns in relation to carbon content. The wide fluctuations and inconsistencies between similar groups indicate that in this subarea, there is no general correlation between higher groups of macrobenthic animals and the quantity of organic carbon in the bottom sediments. Similar fluctuations and inconsistencies were apparent in the analyses of data from both the New York and the Chesapeake Bights. ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 30.-Number of samples for each class of sediment organic carbon in each subarea and for the entire Middle Atlantic Bight region Organic Subarea Tan carson Southern New Chesa- $f (percent to New York peake region nearest 0.1) England Bight 0.01=0.4 93 139 117 349 0.5 -0.9 55 29 26 110 1.0 ~1.4: 14 9 17 40 1.6 «L9 4 6 15 25 S0 +20 1 4 4 9 80 =4.0 .._... 0 0 9 9 BD "T2 0 0 1 1 NG data ' 19 0 1 20 Total .____-. 186 187 190 568 RELATION TO RANGE IN BOTTOM WATER TEMPERATURE This section deals with the relationship between faunal components and the annual range of bottom- water temperature in the Middle Atlantic Bight region. Inasmuch as the data base does not contain a time-series array of temperature measurements, we relied on published sources for these data (see page N12). The normal range of temperature in this region is rather wide, particularly in some of the shallow, inshore locations where the actual tempera- tures may dip slightly below 0°C or rise above 24°C (24°+ temperature range). Range of temperature, as opposed to discrete tem- perature observations made at the time of sample collection, serve as an index of annual change. For analysis purposes, the various annual temperature changes were grouped into seven classes: (1) (2) 4.0°-7T.9°; (8) 8S.0°-11.9°; (4) 12.0°-15.99; (5) 16.0°-19.9°; (6) 20.0°-25.0°; and (7) more than 24.0° change. All references to tem- perature in this section, therefore, pertain to ranges rather than to discrete measurements. A tempera- ture range of 0°-3.9° indicates only that the water temperature variation is not more than 8.9° over the year. TABLE 31.-Mean number of individuals and biomass of the macrobenthic invertebrate fauna in relation to percent organic carbon in bottom sediments for each subarea and for the entire Middle Atlantic Bight region Organic (132222sz to Mean number of individuals per square meter Mean biomass in grams per square meter nearest 0.1) SNE NYB CHB Entire area SNE NYB CHB - Entire area O DLA A .: o. cl Ll il io no ae eee so ae cn n ne ae th e ae e me t e he m 2,643 1,226 1,872 1,653 326 130 TT 164 £0. me dad 3 n. co coc. 1. s ae oe 1s in th ee me te l me m e tt i m n nn n y a, 903 750 623 796 80 79 143 94 0. 1d} ... ... .. .. .. cl lll, ll ll c, ll ol Goed he as oe oe ae tn hace wie se 902 1,208 596 841 65 2,228 66 551 D LD *e. a an ans ance co c. w ie mo ae as me e nn we me or ee tn oe as 2,052 1,061 707 1,007 116 61 63 T1 BM SAD: Lo sons wen a ioe wie ane ae nme in ain 5,236 3,126 182 2,052 218 2,657 14 1,211 3 0 ALD . . .. 1, . c. c. - e 2 ce to e ar on os ine asan m me n we tn ine in i+ -= 597 597 es az 156 156 DA A+ no a i he me ma oe in me ae ae me oo me te e ha me a oe oe e h aa n se aad =~ -- 2,244 2,244 ~ tes 555 555 % -- MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N155 TABLE 32.-Mean number of individuals of each taxonomic group listed by sediment organic carbon content class, repre- senting the entire Middle Atlantic Bight region [In number per square meter] Taxonomic group Sediment organic carbon content (percent) 0.01-0.4 0.5-0.9 1.0-1.4 1.5-1.9 2.0-2.9 3.0-4.9 5.0+ No. /m No. /m No. /m No. /m No. /m No. /m No. /m PORIFERA 0.65 0.17 0.12 = > 1.22 32.00 COELENTERATA 12.59 43.41 8.00 7.56 - 10.78 s Hydrozoa 8.09 22.99 - 0.08 = - C Anthozoa 4.50 20.42 8.00 7.48 n 10.78 & Alcyonacea 0.19 1.15 1.20 0.24 = - a Zoantharia 2.32 6.64 6.08 5.28 10.78 = Unidentified 1.99 12.63 0.72 1.96 = - - PLATYHELMINTHES 0.89 0.05 0.52 - C - m Turbellaria 0.89 0.05 0.52 - - - - NEMERTEA 4.43 3.39 2.95 10.36 0.22 .22 = ASCHELMINTHES 2.99 2.11 1.50 0.68 0.44 - < Nematoda 2.99 2.11 1.50 0.68 0.44 - C ANNEL IDA 355.38 204.20 139.12 137.48 135.22 36.56 548.00 POGONOPHORA 0.01 3,25 14.50 2.68 3.33 - a SIPUNCUL IDA 3.75 5.58 2.22 0.84 0.22 - 2 ECHIURA 0.01 0.47 0.20 0.08 i = > PRIAPUL IDA - 0.02 0.15 - - - _- MOLLUSCA 362.00 147.63 485.02 656.24 909.33 403.33 730.00 Polyplacophora 0.44 0. 35 0.62 0.24 1.22 - - Gastropoda 27.40 14.25 18.22 260.24 52.22 112.11 = Bivalvia 333.36 129.13 463.98 394.60 853.67 291.22 730.00 Scaphopoda 0.79 2.28 2.20 1.16 2.22 ~ C= Cephalopoda 0.01 1.63 - - - - C Unidentified - - - - - - s ARTHROPODA 823.82 308.14 88.62 123.64 994.78 94.22 537.00 Pycnogonida 0.36 0.39 0.28 - 3.11 5.33 - Arachnida 0.07 - - - - - z Crustacea 823.39 307.74 88.35 123.64 991.67 88.89 537.00 Ostracoda 0.26 0.29 - - - - F Cirripedia 10.90 46. 32 - - 885.11 - - Copepoda 0.03 0.05 0.12 - - - - Nebaliacea 0.02 0.01 - - - - Fe Cumacea 19.54 3.12 3.05 0.44 1.22 - - Tanaidacea 0.02 0.23 - - - - _ Isopoda 14.36 4.70 0.40 28.72 10.11 12.11 140.00 Amphipoda 767.29 244.73 83.92 86.00 84.22 76.78 397.00 Mysidacea 2.56 1.89 - 2.20 - - s Decapoda 8.42 6.40 0.85 6.28 11.00 - e BRYOZOA 8.98 1.45 3.80 60.00 = - - BRACHIOPODA 0.01 - - - - - _ ECHINODERMATA 53.02 56.26 80.82 2.72 0.67 - * Holothuroidea 1.62 3.36 4.02 2.28 « = = Echinoidea 35.79 0.39 0.12 - - - a- Ophiuroidea 14.85 51.93 75.48 0.36 .67 - - Asteroidea 0.74 0.58 1.20 0.08 - - - HEMICHORDATA 0.14 0.14 0.25 s > - _ CHORDATA 18.64 11.00 7.00 0.44 6.33 - - Ascidiacea 18.64 11.00 7.00 0.44 6.33 - ~- UNIDENTIFIED 5.34 8.99 5.72 4.32 1.22 49.67 397.00 N156 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 33.-Mean biomass of each taxonomic group listed by sediment organic carbon content class, representing the entire Middle Atlantic Bight region [In grams per square meter] Taxonomic group Sediment organic carbon content (percent) 0.01-0.4 0.5-0.9 1.0-1.4 1.5-1.9 260-219 - 3.0-4.9 5.0+ g/m g/m g/m g/m> g/m g/m g/m PORIFERA 0.056 0.007 0.002 - - 0.012 0.110 COELENTERATA 2.175 5.252 4.687 3.050 - 0.620 - Hydrozoa 0.403 0.225 - 0.001 - - - Anthozoa 1.772 5.027 4.687 3.049 - 0.620 - Alcyonacea 0.026 0.186 0.347 0.148 - - - Zoantharia 1.643 4.375 4.274 2.847 - 0.620 - Unidentified 0.103 0.466 0.066 0.054 - ~- - PLATYHELMINTHES 0.009 <0 .001 0.003 - - - - Turbellaria 0.009 <0 .001 0.003 - - - - NEMERTEA 0.674 0.531 0.239 1.081 0.010 0.012 - ASCHELMINTHES 0.004 0.006 0.006 0.006 0.004 - - Nematoda 0.004 0.006 0.006 0.006 0.004 - - ANNEL IDA 12.449 15.851 11.415 14.018 18.834 3.023 9.770 POGONOPHORA <0.001 0.022 0.094 0.009 0.007 - - SIPUNCUL IDA 0.469 1.116 0.132 2.486 0.004 - - ECHIURA 0.005 0.883 0.471 0.695 - - - PRIAPUL IDA - 0.031 0.039 - - - - MOLLUSCA 108.172 39.215 509.982 45.543 - 1164.252 151.494 540.870 Polyplacophora 0.225 0.012 0.022 0.004 0.004 - - Gastropoda 2.987 3.599 0.390 6.410 11.398 0.052 ~ Bivalvia 104.948 35.532 509.534 39.113, 1152.831 151.442 540.870 Scaphopoda 6.012 0.050 0.036 0.016 0.019 - - Cephalopoda <0 .001 0.022 - - - - - Unidentified - - - - - - - ARTHROPODA 10.299 8.568 0.567 1.550 26.347 0.462 2.250 Pycnogonida 0.002 0.002 0.006 - 0.031 0.027 - Arachnida <0 .001 ~- - - - - - Crustacea 10.296 8.566 0.561 1.550 26.316 0.435 2.250 Ostracoda 0.002 0.003 - - - - ~ Cirripedia 3.912 5.076 - - 20.679 - - Copepoda <0 .001 <0 .001 0.001 - - - - Nebaliacea <0 .001 <0 .001 - a - - - Cumacea 0.073 0.022 0.012 0.004 0.012 - - Tanaidacea <0 .001 0.002 - a - - - Isopoda 0.393 0.099 0.004 0.074 0.076 0.109 1.500 Amphipoda 4.589 2.212 0.518 0.320 0.258 0.326 0.750 Mysidacea 0.015 0.014 - 0.004 - - - Decapoda 1.312 1.137 0.026 1.148 5.291 - - BRYOZOA 0.219 0.020 0.071 2.080 - - - BRACHIOPODA <0 .001 - - - - - - ECHINODERMATA 26.393 14.647 21.929 0.200 0.306 - - Holothuroidea 2.656 9.097 8.532 0.091 - - - Echinoidea 21:102 1.805 0.825 - - - ~ Ophiuroidea 0.909 3.083 6.224 0.107 0.306 - - Asteroidea 1.726 0.662 6.348 0.002 ~ - - HEMICHORDATA 0.034 0.024 0.039 - - - - CHORDATA 3,212 8.139 1.000 0.009 0.479 - ~ Ascidiacea 3.212 8.139 1.000 0.009 0.479 UNIDENTIFIED 0.255 1.920 0.376 0.125 1.062 144% 1.830 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N157 TABLE 34.-Mean number of individuals of each taxonomic group listed by sediment organic carbon content class, repre- senting the Southern New England subarea [In grams per square meter] Taxonomic group Sediment organic carbon content (percent) 0.01-0.4 0.5-0.9 1.0-1.4 1.5-1.9 2.0-2.9 3.0-4.9 5.0+ No. /m No. /m No. /m No. /m No. /m No. /m No. /m PORIFERA 1.13 0.07 0.36 - - - - COELENTERATA 24.02 48.58 16.43 22.00 - - - Hydrozoa 17.11 19.58 - - - - - Anthozoa 6.92 29.00 16.43 22.00 - - - Alcyonacea 0.36 1.11 1.00 - - - - Zoantharia 5.54 4.20 14.93 22.00 - - - Unidentified 1.02 23.70 0.50 - - - - PLATYHELMINTHES 2.61 0.09 - - - - - Turbellaria 2.61 0.09 - - - - - NEMERTEA 6.04 4.38 6.00 - - - - ASCHELMINTHES 9.17 1.96 3.71 - - - - Nematoda 9.17 1.96 3.71 - - - - ANNEL IDA 375.12 264.82 219.79 345.25 131.00 - - POGONOPHORA 0.06 3.05 3.71 - - - - SIPUNCUL IDA 10.64 9.58 2.36 - - - =- ECHIURA - 0.18 0.43 - - - - PRIAPUL IDA - 0.04 0.29 - - - = MOLLUSCA 160.92 87.40 200.98 1078.25 5094.00 - - Polyplacophora 1.59 0.31 0.71 - - - - Gastropoda 53.10 17.31 21.48 217.00 33.00 - - Bivalvia 105.74 65.11 178.64 861.25 5061.00 - - Scaphopoda 0.44 1.42 0.14 - - - - Cephalopoda 0.05 3.25 - - - =- = Unidentified - - - - - - - ARTHROPODA 1908.70 381.66 195.28 217.25 11.00 - - Pycnogonida - 0.78 - - - - - Arachnida - - - - - - - Crustacea 1908.70 380.87 195.28 217.25 11.00 - - Ostracoda 0:37 0.47 - - - - - Cirripedia 40.48 0.38 - - - - - Copepoda 0.06 0.11 0.36 - - - - Nebaliacea - - - - - - - Cumacea 36.57 3.82 8.00 2.75 - - - Tanaidacea 0.09 0.24 - - - - = Isopoda 13.91 2.76 0.86 6.25 - - - Amphipoda 1804.69 368.36 185.35 182.00 11.00 - - Mysidacea 0.80 2.18 - 13.75 - - Decapoda 11.73 2.56 0.71 12.50 - - - BRYOZOA 15.90 0.16 - 375.00 - - = BRACHIOPODA - - - - - - =- ECHINODERMATA 68.91 79.20 225.50 13.75 - - - Holothuroidea 4.26 4.29 11.07 13.75 - - - Echinoidea 14.64 0.56 0.36 - - =- ~ Ophiuroidea 48.57 73.33 213.07 - - =- - Asteroidea 1.44 1.02 1.00 - - - - HEMICHORDATA 0.28 0.27 0.71 - - - = CHORDATA 55.87 5.93 17.43 - - - - Ascidiacea 55.87 5.93 17.43 - - = ~ UNIDENTIFIED 3.77 15.45 8.57 0.50 = i - N158 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 35.-Mean biomass of each taxonomic group listed by sediment organic carbon content class, representing the Southern New England subarea [In grams per square meter] Taxonomic group Sediment organic carbon content (percent) 0.01-0.4 0.5-0.9 1.0-1.4 1.5-1.9 2.:0-2.9 3.0-4.9 5.0+ g/m2 g/m g/m g/m2 g/m g/m g/m PORIFERA 0.090 <0.001 0.007 - - - I COELENTERATA 2.962 8.334 2.994 3.458 - - - Hydrozoa 1.030 0. 348 - - - - - Anthozoa 1.932 7.986 2.994 3.458 - - «- Alcyonacea 0.063 0.200 0.704 - - - - Zoantharia 1.774 7.102 2.185 3.458 - - - Unidentified 0.095 0.684 0.105 - - - - PLATYHELMINTHES 0.014 <0.001 - - - - - Turbellaria 0.014 <0.001 - - - - - NEMERTEA 0.956 0.599 0.378 - - - ASCHELMINTHES 0.008 0.005 0.014 - - - - Nematoda 0.008 0.005 0.014 - - - - ANNEL IDA 18. 383 14.718 9.650 45.445 37.440 - ~ POGONOPHORA <0.001 0.027 0.014 - - - - SIPUNCUL IDA 1.139 2.032 0.196 - - - ~- ECHIURA - 0.079 0.366 - - - - PRIAPUL IDA - 0.062 0.038 - h - ~ MOLLUSCA 241.154 26.045 4.883 44.446 180.130 - - Polyplacophora 0.843 0.004 0.051 - - - Gastropoda 6.246 1.073 0.043 5.888 1.960 - Bivalvia 234.057 24.776 4.785 38.558 178.170 f - Scaphopoda 0.008 0.017 0.004 - - - - Cephalopoda <0.001 0.175 ~- - - - - Unidentified - - - - - ~ ARTHROPODA 26.777 2:723 1.415 8.501 0.110 - - Pycnogonida ~ 0.004 - - - - - Arachnida - - ~- - - - T Crustacea 26.777 2.719 1.415 8.501 0.110 - -~ Ostracoda 0.002 0.005 ~- - - i - Cirripedia 14.674 0.008 - - - f - Copepoda <0.001 <0.001 0.004 - - - ~ Nebaliacea i - - - - - - Cumacea 0.124 0.027 0.028 0.028 - - - Tanaidacea <0.001 0.002 - - - - - Isopoda 0.248 0.122 0.010 0.062 - - - Amphipoda 10.344 2.368 1.369 1.278 0.110 - Mysidacea 0.002 0.024 - 0.008 - - - Decapoda 1.382 0.162 0.004 7.125 - - - BRYOZOA 0.434 0.001 - 13.000 - - ~ BRACKHIOPODA - - - - - ~- - ECHINODERMATA 23.653 19.749 43.389 0.548 - - - Holothuroidea 8.467 13.620 22.195 0.548 - - ~ Echinoidea 10.847 1.167 2.356 - - - - Ophiuroidea 2.830 4.918 15.930 - - - - Asteroidea 1.509 0.044 2.908 - - - - HEMICHORDATA 0.055 0.048 0.111 - - - T CHORDATA 9.428 4.599 1.461 - ~ - - Ascidiacea 9.428 4.599 1.461 i - - - UNIDENTIFIED 0.544 0.280 0.156 0.538 MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N159 4 (2657) 2600 I T I f I I EXPLANATION SNE - x---x 2400} NYB - a-a A CHB @ .- ® ENTIRE 2200) "apga *~--* A ~ z 2000} - 5 CD L - 1800} - O [0 at 85 @ 1600} - Lu C S 3 1400} - V CC L * 41200} V p34 O I 5- f; m <0.04 nd A O L_ 1 Of- c S -loo2 2t- e 73! w. a 5|- i 'A 0 LJ A “ p o C o ol HEELS -__ __ _L _L -L __lp g w t- < HYDROZOA PLATYHELMINTHES " ig) A @ <|0.4 = hat 20|- 0.8|- - L ws 0.008 e 3 < O -10.3 D w | 5}- o.6}|- -]0.006 O © & CC A L <0.2 2. A 1 O- 0.4 |- <10.004 Eli w ® A i z - <0. 1 L ~ 3 5 0.2 0.002 i > o o g L_-sL - otes PgR SIL _ A) fp gl sts teas f®E j 01 past cdc ao & LJ a Pa n ALCYONARIA -----~3 NEMERTEA - 93 a <11.0 3 L 1.4 |- 1 O- st 0 <|0.30 t | 2 ~ o U “08 a o 410.25 8|- u 1.0O}- b [ea) 0.20 _ A 106 i- = 0.8|- A a 6 "x s > <|0.15 A = A - z al- @ -10.4 40.10 \. 0.4|- 5 loos 2|- 'A 40.2 0.2|- a e o | 1 | 1 1 1 N 1 0 o | . \ 1 1 |@A-+a _| o 001 | 10% | 20 | 50 | O01 1; 10 |; 20 ; S50 q 05 15 3.0 10.0 0.5 15 30 10.0 PERCENT ORGANIC CARBON FicUrE 108.-Density (No.) and biomass (wt.) in relation to sediment organic carbon in the entire Middle Atlantic Bight region for Porifera, Hydrozoa, Alcyonaria, Zoantharia, Platyhelminthes, and Nemertea. wWETER Of BOT TOV SQUARE PER OF SPECIMENS N U M B E R MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION ---> NEMATOBA cas ------- SIPUNCULA ----- 3.0|- @ A 412.5 A o 2.5|- -|0.006 s- //\\‘ 412.0 e \ <|0.005 a , A ~- * \ 10.004 +8 1.5)- O i A <|0.003 <1.0 1.o}|- 2|- @ @men No. o 70.002 0.5|- &... Wt. *, !f & o o [. - | L___L___} cns. o 0 1 [* \|.4| 1 o ANNELIDA --->=2 o y spo-----|Ecaiura 5soo|- f -l0.8 o.4|- 400}|- /\ a -! 5 a -<]0.6 "* g// 0.3|- /// 300|- & -|! 0 <10.4 soot. .\ 0.2 o\ ioo} T| ° o.1}- s <|0.2 A t o | 1 1 \ 1 1 1 1 0 0 1 @a | 1 | 1 1 1 o) r---- POGONOPHORA ---- PRIAPULIDA a 40.10 0.20F A <10.04 14} A / 1 2p 410.08 o.15s|- * e 1 o- -|0.06 °C 910 [- <10.02 6[- 410.04 4 A 0.05}|- -10.0 9 40.02 2— A\A @ 0 ths TREC 1 _...... 3... _{ ___ _L cf _j o o meek coid ...... c LL. _ o 001 | 10 | 20 | 50 | 001 | 10 | 20 | 50 | 05 15 30 10.0 0.5 15 30 10.0 PERCENT ORGANIC CARBON N161 PER SQUARE METER OF BOTTOM IN _ GRAMS WET WEIGHT, FIGURE 109.-Density (No.) and biomass (wt.) in relation to sediment organic carbon in the entire Middle Atlantic Bight region for Nematoda, Annelida, Pogonophora, Sipuncula, Echiura, and Priapulida. N162 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES POLYPLACOPHORA --- (Pina sal ~~~ OLYPLA : o sar SCAPHOPODA 35 ss ig ._ NO. 0.29 2.5}- 1.8 Ais seme NL > .§.‘ M 410.04 3 a 2.0 |- & 410.15 <10.03 s i- 1.0} 1.5} C 0 - m 410.10 94 10.02 g o 1.0f '& ~*~ s 0.5 / 2 u 0 "CIR & 40.05 sl uw y s \. - o st. 0.01 Cs /A Lil: 0 | | 1 1 \IA—+-A | 1 0 1 I | | | | | | o I5 LJ i- 3 -----~-GAST e (e" , S ROPOQA Z sof CEPHALOPODA jo bse = 250|- a 410 E < © 410.025 ? > 200 |- 1.5} a a iC 2 -| 0.020 sd 150 A L g § 1.0} flogs, G a. @ a. 100 |- 4 4 e oA - 0.010 53 P a A 0.5 > w 50}|- I & 12 10.005 __ < 3 ) & 8 o | | [*"! & | | l A | o 0 | @t _| 1 | | 1 | 0 $ $ £ () BIVALVIA mer ~~ -~~AIrs00 ---; :PYCNOGONIDA % 6 [- 410.04 gL LL I 0 eo9 e-|!999 5|- g C. ra A <10.03 g bd 600 -| 800 4 |- A c - 3 [; _ L 1 soch 0\\. -| 600 3 hd 0.02 3 1 @ -| 400 2|- < 200}|- \ -|0.01 % -|200 1 - aA * mat oL-__iz1 R | .- (ee.. o ol- 1 1 _i _i Uo O01 |: 10 | 20 4 "S0 | O01 | 10 ; 20 | - 50 % 05 18 30 10.0 05 15 S0 10.0 PERCENT ORGANIC CARBON FIGURE 110.-Density (No.) and biomass (wt.) in relation to sediment organic carbon in the entire Middle Atlantic Bight region for Polyplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda, and Pyenogonida. MACROBENTHIC INVERTEBRATE 0,30 0,25 0.20 METIE R__O.F_ B OIT O M 800 SQUARE 600 PCR 400 200 S PECIME NS 0.12 0.10 0.08 NV MBE R __OF 0.06 0.04 0.02 FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION <~10.0030 COPEPODA . 1 | i I 1 1 I C OSTRACODA ® @amnm No. L- A _] | | | | | | 1 1 CIRRIPEDIA CA -I 1 1 0.0025 0.0020 0.0015 0.0010 0.0005 2.0 0.0014 0.0012 0.0010 0.0008 0.0006 0.0004 0.0002 20 | 50 | 30 10.0 0.20|- NEBALIACEA 410.00020 #A e" 0.05;- A 0.010 |- -0.00010 0.005;- -10.00005 o | 1 1 I 1 1 1 I 0 0.20|- e CUMACEA 10.08 O,.L5- <10.06 40.04 0.05|- \ -10.02 @uomQ® z o 1 1 1 1 1 o gast TANAIDACEA sp @ A 0.20|- -10.0015 O.1J5F- 410.0010 0.1 Of- -10.0005 0.0 5;- OA o | 1 . 1 1 1 1 1 0 001 | 10 | 20 | 50 | 05 15 30 10.0 PERCENT ORGANIC CARBON N163 IN GRAMS PER SQUARE MCTER OF BOTTOM WET WEIGHT, FIGURE 111.-Density (No.) and biomass (wt.) in relation to sediment organic carbon in the entire Middle Atlantic Bight region for Ostracoda, Cirripedia, Copepoda, Nebaliacea, Cumacea, and Tanaidacea. N164 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES nat I{SOPOBDA ------- ——————*-DECAPODA-——"————— f 1 of [Ni.« J 1.2|- - @mem No. A sme: YVE? ~t!-£ 8|- 1.0 - \ ~14 3 (@] o O.8- -lo.s 6|- ~13 3 i- R O 3 - het 0.6|- <10.6 al. > g e 0.4} A <10.4 (3 C ® I 2 [- % 4 es /\ - hag I |- I Of- o < > n—Q—O—x/ A C w \ z & g_ __ S4 ima o olka a x44 1 men tet % LW . MYSIDACEA RACHIOPODA --- 4 de 3.0|- 40.020 | 0.006 BRAC Ja.00co0s _ | - Lz bes x 0 2.5|- o 0.005}|- -|0.00005s _ 2 <0.015 L1 o e L 2.0|- \A/ 0.004}- -10.00004 - = c ®. - S LW ad 1.5}- A <10.010 0.003|- -|0.00003 _ = z 1.Of- 0.002|- -10.00002 -10.005 0S- & 0.001 |- -10.00001 o 1 | | | I | | 1 0 0 1 \ | | | 1 1 1 (o) 901 1 10} 1 zo j "59 ; O01 1 10 ; 20 |. so | 05 15 30 10.0 05 15 30 10.0 PERCENT ORGANIC CARBON FIGURE 112.-Density (No.) and biomass (wt.) in relation to sediment organic carbon in the entire Middle Atlantic Bight region for Isopoda, Amphipoda, Mysidacea, Decapoda, Bryozoa, and Brachiopoda. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION HOLOTHUROIDEA ASTEROIDEA Arn 2.0|- A 46 A al @ meam No. 71° 415 / A-- Wt, 1.5} > @ 46 414 O - -- * A +1 1. 0- 4/3 0 f -|4 co 2|- o o. * s , ~s § O -|2 94 r \ - 1 o 'A L {t glas ifc c ua ttr Baur rll Slig gL _L f EROL _L __ t_ 1+ L 3 ECHINOIDEA remains HEMICH@ORDATA ___.... ti} 35|- aa 0.25|- 10.05 at -|20 < 30|- ma 0.20|- A 10.04 2 25}- 415 A i sol- O.15- .\. 410.03 L 110 A & I 5}- 0.1 0|- -lo02 U 1 Of- Z - 5 12) 0.05|- 0.01 3 x o ol _L on ess®@a p UUU o gls n Juul hlp LJ a n 80 - OPHIUROIDEA I ASCIDIACEA a 65 400 |- 3 = s G 300 |- A UJ 3 +— LJ € 20 - wel // _ z 100 |- Be x/ a | //:’ G 2&4 | | | § | | 4 8 12 16 20 24 28 RANGE IN BOTTOM-WATER TEMPERATURE , IN DEGREES CELSIUS FIGURE 116.-Relation between biomass and range in bottom-water temperature. Values represent all taxonomic groups combined for each subarea and for the entire Middle Atlantic Bight region. Abbreviations: SNE, Southern New England; NYB, New York Bight; CHB, Chesapeake Bight. N170 SUBAREAS sOUTHERN NEW ENGLAND The mean density of all organisms in each tem- perature-range class, except one, was higher in Southern New England than in the two other sub- areas. The exception was in the 8°-11.9°C class, where density in Chesapeake Bight slightly exceeded that in Southern New England (1,006/m' versus The relationship between density and broadening temperature range was also most con- sistent in this subarea. Mean values of density in- creased steadily (174/m*, 960/m*, 2,797/m, and 3,235/m?) as temperature range widened until 16°-19.9°C was reached; values then declined slightly (2,475/m' in 20°-28.9°C, and 2,861/m in 24°+C). In almost all temperature-range classes, the mean biomass was larger than those in either New York Bight or Chesapeake Bight. In the 0°-8.9°C class, Chesapeake Bight had a slightly larger biomass (11 versus 10 g/m?) than Southern New England, but the greatest disparity, which may simply be due to sampling variability, was found in the 20°-23.9°C class, where the biomass in New York Bight was significantly larger than that in Southern New Eng- land (704 versus 156 g/m*). Except for the two examples just mentioned, mean biomass in Southern New England was generally larger than those in New York Bight and Chesapeake Bight and tended to increase as temperature range broadened. Smallest average biomass (10 g/m") was found in 0°-3.9°C class, and largest (1,011 g/m?) in the 24° +C class. Biomasses ranging from 67 to 409 g/m were found in the intermediate classes, table 37. NEW YORK BIGHT Although the general tendencies of macrofaunal density in the New York Bight subarea were to in- crease as temperature range increased and to fall between those of Southern New England and Chesa- peake Bight, some notable exceptions were seen. Density values increased in the first four tempera- ture classes (0°%-3.9° to 12°-15.9°C) from 124/m to 1,408/m>; dipped to 870/m in the 16°-19.9°C class; rose again to their highest point, 2,143/m, in the 20°-23.9°C class; then decreased again to 1,471/m in the broadest range. Comparatively, the mean den- sity of organisms in New York Bight in the first three temperature classes (0°%-8.9° to 8°-11.9°C) was the lowest of the three subareas, and Chesa- peake Bight occupied the intermediate position; but in the remaining classes, the density of New York Bight fell between the densities of Southern New England and Chesapeake Bight. ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES The average biomass of all organisms in New York Bight was very similar to that of Chesapeake Bight in the narrow to moderate temperature classes (0°-8.9° to 12%-15.9°C), ranging from 8 to 148 g/m"; was between those of Southern New England and Chesapeake Bight in both the 16°-19.9° and 24° +C classes (161 and 392 g/m", respectively); but was largest (704 g/m?) of any subarea in the 20°-283.9°C class. CHESAPEAKE BIGHT The relationship between mean density and bio- mass of all organisms and range in temperature was least consistent and generally lowest in this subarea. Densities in the first three classes tended to increase (76/m2, 612/m, and 1,006/m*) as range broadened, culminating in the greatest density in the 8°%-11.9°C class of any of the subareas. Values between 398/m* and 1,692/m* were found in the other temperature classes, but showed no definite pattern, and, overall, were lower than in the other subareas. Biomass values in the first four temperature classes (0°%-3.9° to 12°-15.9°) paralleled those of Southern New England and New York Bight very closely both in the general trend of increasing as temperature range broadened and in amount, which ranged from 11 to 137 g/m". However, in the broader classes, both the trend and the mean of biomass values fell drastically, except in the 24°+C range, where the largest biomass (149 g/m*) in this sub- area was recorded. See figure 116 and table 37. TAXONOMIC GROUPS ENTIRE MIDDLE ATLANTIC BIGHT REGION This section deals with the relationship between the mean density and biomass of each taxonomic group in the entire Middle Atlantic Bight region and the range in bottom-water temperature. Densities of each taxonomic group by temperature class are listed in table 38. Corresponding biomass values for each taxonomic group are listed in table 39. These data are illustrated in figures 117 through 122. SUBAREA DIFFERENCES IN DISTRIBUTION OF TAXONOMIC GROUPS This section deals with the relation of temperature range to each taxonomic group within each of the three subareas. Density data listed by temperature- range class are presented separately for each sub- area in tables 40, 41, and 42; corresponding biomass values are listed in tables 43, 44, and 45. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N171 TABLE 38.-Mean number of individuals of each taxonomic group listed by temperature-range class, representing the entire Middle Atlantic Bight region [In number per square meter] Taxonomic group Range in bottom water temperature (°C) 0°-3.99 4.0°-7.99° _ 8.09-11.99 12.0°-15.99 16.0°-19.99 20.00-23.99° - 24.0°+ No . /m2 No . /m2 No. /m2 No . /m2 No . /m2 No . /m2 No . /m2 PORIFERA 0.07 0.65 9.73 0.48 0.14 0.62 1.75 COELENTERATA 3.69 16.06 10.12 20.28 8.22 17.21 53.10 Hydrozoa 0.02 1.94 2.15 11.95 5.91 12.16 24.84 Anthozoa 3.67 14.12 6.97 8.33 2.30 5.06 28.26 Alcyonacea 1.10 2.71 1.24 0.77 - - - Zoantharia 0.85 9.53 4.18 6.60 1.78 4.15 4.37 Unidentified 1.72 1.88 1.55 0.96 0.52 0.91 23.90 PLATYHELMINTHES - - 0.45 0.37 3.05 0.21 0.46 Turbellaria - ~ 0.45 0.37 3.05 0.21 0.46 NEMERTEA 0.70 2.82 2.64 6.21 7.58 5.78 3.00 ASCHELMINTHES 1.09 0.53 0.45 2.50 10.77 0.40 2.90 Nematoda 1.09 0.53 0.45 2.50 10.77 0.40 2.90 ANNEL IDA 52.65 237.71 188.61 330.29 341.84 469.56 273.22 POGONOPHORA 5.17 1.29 2.33 3.95 - 0.04 - SIPUNCUL IDA 4.12 11.18 4.88 6.11 7.19 0.46 2.24 ECHIURA 0.35 - - - - 0.30 - PRIAPUL IDA 0.07 - - - - - - MOLLUSCA 46.64 213.47 130.82 157.70 113.29 832.22 421.84 Polyplacophora 0.45 - 0.42 0.98 - 0.04 1.26 Gastropoda 6.76 3.35 13.79 10.98 13.72 92.50 35.91 Bivalvia 36.53 205.71 107.27 143.37 99.44 739.38 384.66 Scaphopoda 2.90 4.12 3.91 1.33 0.13 0.30 - Cephalopoda - 0.29 5.42 - - - a Unidentified - - - 1.04 - - - ARTHROPODA 7.27 57.53 324.24 1402.02 1130.56 551.00 455.19 Pycnogonida - - - 0.12 0.67 0.41 2.59 Archnida - = = - - 0.17 - Crustacea 7.27 57.53 324.24 1401.90 1129.89 550.42 452.60 Ostracoda 0.05 - - 0.21 - 0.47 0.34 Cirripedia - - - 0.22 45.42 86.18 0.31 Copepoda 0.10 - 0.12 0.06 - - - Nebaliacea 0.02 - - - 0.05 0.01 - Cumacea 0.97 5.94 12.61 32.68 35.00 14.10 1.04 Tanaidacea 0.30 - - - - - - Isopoda 0.54 1.59 3.88 9.06 26.70 18.84 11.63 Amphipoda 5.17 46.29 305.36 1352.94 1018.78 411.23 424.09 Mysidacea 0.02 - - 0.06 0.05 4.58 6.47 Decapoda 0.10 3.71 2.27 6.68 3.89 15.00 8.82 BRYOZOA - - 5.27 1.85 27.19 21.36 15.90 BRACHIOPODA - - - - 0.02 - - ECHINODERMATA 5.46 46.07 171.09 114.75 29.56 60.11 6.54 Holothuroidea 1.69 4.42 2.42 7.13 0.16 0.82 0.07 Echinoidea 0.07 1.00 1.62 14.43 27.05 58.30 5.10 Ophiuroidea 3193 39.82 164.27 91.42 0.71 0.60 1,25 Asteroidea 0.16 0.82 2.88 1.76 1.63 0.39 0.12 HEMICHORDATA 0.05 - 0.15 0.40 - 0.16 - CHORDATA 1.26 1.18 3.97 20.33 17.19 19.75 22 A7 Ascidiacea 1.26 1.18 3.97 20.33 17.19 19.75 22.17 UNIDENTIFIED 4.34 2.53 5.42 6.11 5.84 7.51 18.04 Porifera in the Southern New England subarea | low, ranging from 0.13/m' to 7.5/m* in Southern occurred in all temperature classes except 12.0°- | New England, from 0.25/m to in New York 15.9°C. They were found in only four classes in New Bight, and from to 0.6/m* in Chesapeake York Bight: the 8.0°%-11.9°, 12.0°-15.9°, 20.0°-23.9%, | Bight. No increase in density was apparent as tem- and 24.0°+C classes. In Chesapeake Bight, they | perature range broadened, although the highest den- were found in only three of the temperature classes: | sities in the two northern subareas were found in 0°-3.9°C, 20.0°-23.9°, and 24.0° +C. The density of | the broadest temperature-range class. The biomass sponges in each of the subareas in the Middle At- | of sponges was small in all three subareas. lantic Bight region was moderate to moderately N1T42 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 39.-Mean biomass of each taxonomic group listed by temperature-range class, representing the entire Middle Atlantic Bight region [In grams per square meter] Range in bottom water temperature (°C) Taxonomic group 0°-3.99° 4.0°-7.990 8.0°-11.99 12.0°-15.99 16.0°-19.9° 20.0°-23.99 24.00+ 2 2 2 2 2 2 2 g/m g/m g/m g/m g/m g/m g/m PORIFERA 0.018 0.035 0.033 0.044 0.163 0.047 0.069 COELENTERATA 0.536 1.376 13.093 1.972 0.465 2.766 7.306 Hydrozoa <0.001 0.067 0.014 0.073 0.150 0.464 1.090 Anthozoa 0.536 1.309 13.079 1.899 0.315 2.302 6.216 Alcyonacea 0.145 0.122 0.298 0.227 - - - Zoantharia 0.214 1.096 12.639 1.552 0.172 2.198 5.822 Unidentified 0.177 0.091 0.142 0.120 0.143 0.104 0.394 PLATYHELMINTHES - - 0.004 0.013 0.019 0.004 0.006 Turbellaria - - 0.004 0.013 0.019 0.004 0.006 NEMERTEA 0.070 0.170 0.456 0.648 0.945 1.018 0.372 ASCHELMINTHES 0.006 0.004 0.002 0.004 0.007 <0 .001 0.012 Nematoda 0.006 0.004 0.002 0.004 0.007 <0.001 0.012 ANNEL IDA 2.553 8.539 7.778 20.046 12.917 18.093 18.281 POGONOPHORA 0.028 0.008 0.005 0.033 - <0. 001 - SIPUNCULIDA 1.777 0.589 0.172 1.082 0.546 0.019 0.302 ECHIURA 0.995 - - - - 0.200 - PRIAPUL IDA 0.045 - - - - - ~ MOLLUSCA 0.668 2.500 44.608 94.656 149.427 242.580 238.765 Polyplacophora 0.005 - 0.004 0.014 - 0.004 1.149 Gastropoda 0.078 0.031 0.059 4.865 0.815 6.221 3.013 Bivalvia 0. 540 2.405 44.411 89.736 148.611 236.351 234.603 Scaphopoda 0.045 0.061 0.060 0.037 <0.001 0.004 - Cephalopoda - 0.003 0.074 ~ - - - Unidentified - - - 0.004 - - - ARTHROPODA 0.068 0.668 1.816 7.867 27.728 10.865 4.842 Pycnogonida - - - 0.001 0.002 0.003 0.016 Arachnida - - - - - <0. 001 - Crustacea 0.068 0.668 1.816 7.866 27.726 10.861 4.826 Ostracoda <0.001 - - 0.001 - 0.004 0.003 Cirripedia - - - 0.004 17.055 4.944 0.006 Copepoda <0. 001 - <0.001 <0. 001 - - - Nebaliacea <0. 001 - - - <0.001 <0.001 - Cumacea 0.009 0.046 0.067 0.191 0.113 0.048 0.005 Tanaidacea 0.002 - - - - - - Isopoda 0.015 0.079 0.215 0.301 0.807 0.304 0.178 Amphipoda 0.029 0.137 1.441 6.286 8.806 3.205 2.730 Mysidacea <0. 001 - - 0.002 <0. 001 0.017 0.034 Decapoda 0.011 0.406 0.092 1.081 0.944 2.339 1.870 BRYOZOA - - 0.072 0.031 0.930 0.656 0.074 BRACHIOPODA - - - - <0.001 - - ECHINODERMATA 2.678 26.076 32.712 36.910 44.558 22.415 0.861 Holothuroidea 1.710 5.461 1.263 21.355 5.876 0.417 0.048 Echinoidea 0.190 12.372 13.120 6.675 38.513 19.870 0.355 Ophiuroidea 0.741 7.825 10.459 3.962 0.017 0.160 0.317 Asteroidea 0.037 0.418 7.870 4.918 0.152 1.968 0.141 HEMICHORDATA <0. 001 - 0.046 0.076 - 0.044 - CHORDATA 0.139 0.071 0.527 2.042 1.621 4.357 15.495 Ascidiacea 0.139 0.071 0.527 2.042 1.621 4.357 15.495 UNIDENTIFIED 0.128 0.142 0.073 0.450 0.270 0.310 0.297 Coelenterata were found in each of the three sub- areas in all temperature-range classes except the 24.0°+C class in New York Bight. Since the co- elenterates are made up of several subcomponents, a detailed analysis will be given under the separate components. Coelenterates, as a group, were signifi- cant contributors to the overall macrofauna in all three subareas in both density and biomass. | _- Hydrozoa in Southern New England were present i in all classes except the 0°-3.9° and 8.0°%-11.9°C MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N173 r------_ PORIFERA ------ ZOANTHARIA 2.0L jo" "%. A log 112 @ mam NO. @ | t 8a |- 16 15. *- Wt. & 10.12 t's O 6 F- & ps 5 t9f 0.08 § 9 2 s » n al f 3 0.5 P A 2/ 71 * C O + ‘\A/“ -I 006 2 |- _ 2 L5 o \ f o L 4-154... sut £4 __t t Lip pl-4 rere 1 o a z y < _ HYDROZOA - -----y --- _ PLATYHELMINTHES --- t 25[- ea - 10.12 a |- lb0%0 . % LJ a 0.10 A e < " V: &. 20 > I 3} f - 3 in 40.08 o 15} A v2 E 4 0.06 2 [ - 0.010 & . LJ a 10} \/ a. 1004 v s / 1} 4 e* joocs 2 Z | 4002 < § S a @ & t 0 11‘4 “PA/f lee o o {pth oa outh cde. df 1 8" ; ___4 o & LJ a -A ALCYONARIA ------_ NEMERTEA s= T 3.0 |- o 40.30 8 |- 2 F o ~ 1 1.0 +- L m 0 2.5} 10.25 /\ w 6 |- < 10.8 t & ® 3 L 2.0} 40.20 [se) E 10.6 = 15} {0.15 a} > D z 104 1.0} 40.10 74 % 2 L ost 40.05 // 10.2 a. O 1 1 1 1 1 I | | O O | | L 1 1 l 1 | O 0 4 8 142 16 20 24 28 0 4 8 12 16 20 24 28 ANNUAL RANGE IN BOTTOM -WATER TEMPERATURE, IN DEGREES CELSIUS FIGURE 117.-Density (No.) and biomass (wt.) in relation to range in bottom-water temperature in the entire Middle Atlantic Bight region for Porifera, Hydrozoa, Alcyonaria, Zoantharia, Plathyhelminthes, and Nemertea. classes. In New York Bight, their presence was de- | present in all the broader range classes, but were tected in all classes except the 4.0°%-7.9°C and the | absent in the two narrowest (0°-3.9° and 4.0°- 24.0°+C classes. In Chesapeake Bight, they were | 7.9°C). Among the three subareas, mean densities N174 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES NEMATODA % fof a Igest sr ~> SIPUNCULA @ man No. 10 A 41.6 SJ B nome WA 5 410.015 3 8[- 11.2 S 6)|- A A € E - “0.0|O 6r— O 0 al- y 410.8 C 8 A 4|- 0 & 'A 8 L. h so 3 e_ \‘ $ e 0.005 $ Jl6a t \‘/ 2|- 0 o *a, es {A e ol _L __T#®®=# |___| o _L ___ Ls Le aM l s lp o Li i- 3 ANNELIDA ------- o z- e A a Also osl a ECHIURA Jie S i s us s 400 |- o & > 4/15 0.3|- t | wa 3 0 6 0 w 300|- A. i & 40.6 & @ 4110 02|- C L f LW a 200(- § 404 a ( & Z 100o}|- ° 8p a L. S4 Aa a 5}- & a -d 3 006|- 'a u 1 qL. A ma L hd 5 10,03 +- L i S- -0.02 0.04 |- s z 0 40.02 2 - -|0.01 0.02} [L A\‘ 10.01 o f. F _d p _L __} Jim! ... ! 0 o hrn fo cod.... L..... Lis of.. _L cl (o) 0 -4 8 12 46 20 24 28 0 4 °B 12 16 20 24 28 ANNUAL RANGE IN BOTTOM-WATER TEMPERATURE, IN DEGREES CELSIUS FIGURE 118.-Density (No.) and biomass (wt.) in relation to range in bottom-water temperature in the entire Middle Atlantic Bight region for Nematoda, Annelida, Pogonophora, Sipuncula, Echiura, and Priapulida. were higher in Southern New England and Chesa- | class to a high of 153/m? in the broadest class, peake Bight and somewhat lower in New York | 24.0°+C. In New York Bight, the lowest density Bight. In Southern New England, the range of den- | value (0.06/m*) was in the 0°-8.9° class and the sities was from a low of in the 12.0°-15.9°C | highest (11/m"') was in the 20.0°-283.9°C class. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N175 f POLYPLACOPHORA --- ------ SCAPHOPOD/A : ----- 2.0|- A 5 |- <0.0 7 @mmm No. -11.0 A--A -|0.06 sL A- Wt a |- /0~. z R -|o.8 / 40.05 T al , -|0.04 p- -lo.e y L- 1.0}- e 6 A 0 O -l i- CO 2 - 0.03 _ <10.4 0 Lw <10.02 c 0.5} +3 p O ._. —O 2 I L Lc AV 6 40.0 1 0 LW F o o (e* . o & LW LJ 3 1 00r----- GASTROPODA ----<- CEPHA D t i 6 <6 s[- LOPODA <10.08 e o 8 t < 8o|- <5 5|- C& -D | J J 0 0 0 . | | 1 1 1 1 0 Q Z w BIVALVIA -------4250 --- PYCNOGONIDA ----- - | Oa- 3.0}|- 42,0 700 A s LL. m 24 a e6oo|- <1200 2.5|- & & -| 1.5 L a 500|- 2.0|- g (3 a -150 F— p 400- L = & 1.5+- 11.0 3 2 300|- £ -| 100 1.0} 200|- o / -0.5 a' -e -| 50 ®, 1 00|- \. 0.5}- / > A o Afucts # }.}. fat coed o o J NS L... ile p 0 -|. _ j o O 4 8 12 16 20 24 28 O 4 8 12 16 20 24 28 ANNUAL RANGE IN BOTTOM-WATER TEMPERATURE, IN DEGREES CELSIUS FIGURE 119.-Density (No.) and biomass (wt.) in relation to range in bottom-water temperature in the entire Middle Atlantic Bight region for Polyplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda, and Pyenogonida. Chesapeake Bight contained relatively high densities, | sity values were highest in the broader ranges, ranging from a low of 3/m>? in the broadest tempera- | whereas, in Chesapeake Bight, highest values were ture range to a high of 123/m> at midrange. In both | recorded in the midrange classes. Biomass values for Southern New England and New York Bight, den- | hydroids paralleled density values in that they were N176 0.5 0.4 > O 0.3 ’_ f— O m 0.2 U; i o: [bet L +- 0 L > Lu ® 80 < D O hys 60 CC L 40 a ( z 20 LW 3 O 0 L a w iL. 0.14 O O.1 2 C T 0.1 0 CO pg 0.08 22 -> 0.06 0.04 0.02 0 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES ~ OSTRACODA .— No. f Wt f =d | | | | | 1 | | ClRRlPEDIA [s m 7 | 1 COPEPODA A - C A -I [~ & - . A - h E 1 1 l l 1 | | 1 0.004 0.003 0.002 0.001 0.0008 0.0006 0.0004 0.0002 6 (4. "8 12 416 20 24 28 cuet - NEBALIACEA E cose 0.05|- @4A -|0.00025 0.04|- A be: 0.03|- -0.00015 G }—. A i- 0.02|- 6 -0.00010 8 0.01} ad -/0.00005s 5 Lant Te iene... det te} e on tage 1 t 0 0 t - CUMACEA Uj 35|- 40.20 S LJ 30|- (2. W < agl 0.15 5 0 20 |- ¥ 40.10 C | L a 1 O|- <0.05 C 3 5|- @ a / CC o { " 1... 34.) 1 ..... ad ca Mik A -L) C) c # osel TANAIDACEA -= . # C 0.25 |- (G] a ye 0.20|- - z - 0.15|- -|0.0015 nea 3 0.10|- -|0.0010 0.05}- -|0.0005 0 1 1 Cd | T | | | 0 0 4 8 12 16 20 24 P8 ANNUAL RANGE IN BOTTOM-WATER TEMPERATURE ,IN DEGREES CELSIUS FIGURE 120.-Density (No.) and biomass (wt.) in relation to range in bottom-water temperature in the entire Middle Atlantic Bight region for Ostracoda, Cirripedia, Copepoda, Nebaliacea, Cumacea, and Tanaidacea. higher in both Southern New England and Chesa- peake Bight than in New York Bight. The mean biomass in Southern New England was smallest (0.1 g/m) in the 12.0%-15.9°C class and largest (4.3 g/m?) in the broadest class. In New York Bight, biomass ranged from trace amounts in the 0°-3.9°C MACROBENTHIC INVERTEBRATE FAUNA I1SOPODA 30} A <|0.8 @ emm No. F 220 -.- MiGente WT: i 20, & s 1s|- \ -l0.4 0 % ig i o|- A 4 ts A7 \ <0.2 0 £ 'A § [/» ¥ o | ___ u g b p LJ y AMPHIPODA ----- | 41- ® A LJ ho 1 2|- 18 < D 1 O- © [aj 4 U (D 6 8... & L 6|- -|4 o ~ is 4|- @ m: Ga # [j -|2 LW 2+ A = f a o IP "A-1 "« L 1 1 | A. o L . M 0 YSIDACEA Taos & L5 6|- A 6 <|0.03 $t L. L # c 4 |- > -10.02 3 z- z -10.01 | L- o | &a st qauws @a | ____|____|____| o 0 4 8 12 16 20 24 28 ANNUAL RANGE IN BOTTOM-WATER TEMPERATURE, IN DEGREES CELSIUS OF THE MIDDLE ATLANTIC BIGHT REGION DECAPODA a | 4 [- -10.20 1 2t A i O- 10.15 # 8.— -~40.10 6} “V 4— @ & -<40.05 6 /A\./ o |‘/|\IA 1 1 1 p _ | 0 BRYOZOA 0.10 30- A 25|- \ -|0.08 20|- -|0.06 1 5}|- & -10.04 1 O- 410.02 5|- .\ o p ___} 1 T: | | [A | 0 BRACHIOPODA ----- 0.0 30|- -10.00030 0.025|- #2 -|0.00025 0.020|- -0.00020 0.015|- -0.00015 0.010} 0.005|- ~10.00005 0 | I | 1 | | 0 1 | O 4 8 A2 16 20 24 28 N177 WwET WEIGHT, IN GRAMS PER SQUARE METER OF BQT TOM FIGURE 121.-Density (No.) and biomass (wt.) in relation to range in bottom-water temperature in the entire Middle Atlantic Bight region for Isopoda, Amphipoda, Mysidacea, Decapoda, Bryozoa, and Brachiopoda. class to 0.2 g/m" in the 20.0°%-23.9°C class. Chesa- | g/m" in the 8.0°%-11.9°C class to 0.57 g/m* in the peake Bight biomass of hydroids generally increased as temperature range broadened, going from 0.04 24.0°+C class. N178 HOLOTHUROIDEA ASTEROIDEA 1 of- ps 20 3.0|- 4 -|8 @ mem No. Ah sstme . L- 6) Wt 25 -<15 -/6 S A 2.0|- C °F ‘x. a i- 10 1.9 -|4 S y ¢ 1.0} 8 LL 0 5 0 A -|2 o C ¥ o ol. \|0Al o y LJ i- > iaa L 40 HEMICHORDATA -e LJ A 365 > L fr 04 g C3) 30 -lo.06 o D 25 0.3|- f A s 20 z -|0.04 x a 0.2;- a. 15 J. o (#) W Z o 0.1 |- 9.02 l Ld 4 3 5 @ [esi O o o Jolie d.... 3, 1 | 1 Tec 0 GO a Z 3 OPHIUROIDEA ASCIDIACEA s 16o|- oa 10 25}|- _ Us 414 T G w 4 g 20}- 0 a ~12 3 - A LJ 4 120 \./ = L 410 c - 6 1 5}- i- = L a so|- { < > A -| 4 Me) m 16 A M 4 40 /o {> s / 2 p* pk o J-Jo 2=,—l-A/| (Meares isl __| o o- 4i /m 12 16 20 24 28 0 4 B 12 16 20 24 286 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES ANNUAL RANGE IN BOTTOM-WATER TEMPERATURE, IN DEGREES CELSIUS FIGURE 122.-Density (No.) and biomass (wt.) in relation to range in bottom-water temperature in the entire Middle Atlantic Bight region for Holothuroidea, Echinoidea, Ophiuroidea, Asteroidea, Hemichordata, and Ascidiacea. Anthozoa were present in all temperature-range classes in both Southern New England and Chesa- peake Bight subareas and in all but the 24.0°+C class in New York Bight. Densities were quite simi- lar in both Chesapeake Bight and New York Bight, but were considerably higher in Southern New Eng- MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION land. The range of densities in Southern New Eng- land was from 1/m' in the 16.0°-19.9°C class to a high of 123/m? in the 24.0°+C class. Densities in New York Bight ranged from a low of 0.4/m> in the 12.0%-15.9°C class to a high of 9/m* in 4.0°-7.9°C. In Chesapeake Bight, the range of density was from 2/m? in the 12.00-15.9°C class to 18/m' in the 24.0°+C class. Average biomass as well as density, was larger in Southern New England than in the other two subareas, ranging from a low of 0.07/m in the 16.0°-19.9°C class to a high of 31 g/m in the 8.0°-11.9°C class; intermediate values occurred in the other classes. In New York Bight, the smallest bio- mass (0.19 g/m?) was found in the 12.0°%-15.9°C class and largest (4 g/m) was in the 8.0°%-11.9°C class. In Chesapeake Bight, the smallest biomass (0.9 g/m) was in the 4.0°%-7.9°C class and the highest, 7.2 g/m, in the broadest temperature range. Alcyonacea were most prevalent in Southern New England, where they were found in four of the seven temperature classes. They were found in only three classes in New York Bight, and in only one class in Chesapeake Bight. Densities and biomasses of alcyonaceans were moderate to moderately low. Their density in Southern New England ranged from in the 0°-8.9°C class to 2/m* in the 8.0°- 11.9°C class; whereas, in New York Bight, slightly higher densities ranged from 0.9/m' in the 8.0°- 11.9°C class to 7/m> in the 4.0°%7.9°C class. In Chesapeake Bight, alcyonaceans were found only in the 0°-3.9°C class, where their density was 0.8/m*. The biomass was moderately low, ranging from 0.04 to 0.4 g/m? in all three subareas. Zoantharia were found in all temperature-range classes in Southern New England, in all but the broadest class in the New York Bight, but were present in only three classes in the Chesapeake Bight (16.9°-19.9°, 20.0°-28.9°, and 24.0°+C). Highest densities were found in Southern New England, where the average density ranged from nearly 1/m* to whereas, in New York Bight, they ranged from 0.2/m* to 8/m'. Chesapeake Bight contained the fewest number of individuals; densities ranged from 0.4/m to 5/m*. Biomass was parallel to density in that biomasses were largest in Southern New England, intermediate in New York Bight, and mod- erately low in Chesapeake Bight. In Southern New England, biomass values ranged from 0.05 to 30 g/m; in New York Bight, from a low of 0.004 to a high of 3.4 g/m; and in Chesapeake Bight, from 0.1 to 7 g/m. In Southern New England and New York N179 Bight, the largest biomass was found in the mid- range class, 8.0°%-11.9°C. However, in Chesapeake Bight, the zoantharians were restricted to the broader range classes. The relationship between Platyhelminthes dis- tribution and temperature range in each of the three subareas was slightly different. In Southern New England, they were found in three classes, from 12.0° to 28.9°C; in New York Bight, they were found in only two classes, 12.0°%-15.9° and 20.0°- 23.9°C; and in Chesapeake Bight, they were found in four classes, 8.0°-11.9°C and the three broader range classes from 16.0°-24.0°+C. Densities were low to moderate (0.04/m* to 8/m?); the densities were higher in both Southern New England and Chesapeake Bight than in New York Bight. Biomass in the three subareas was small (0.002 to 0.04 g/m"), and both Southern New England and Chesapeake Bight contained larger biomasses than those in New York Bight. Nemertea were found in all temperature ranges in each of the subareas of the Middle Atlantic Bight region. Densities of these organisms were generally higher in Southern New England than in the other two subareas; although, among the various tempera- ture ranges in all areas, the distribution of density values was fairly equitable. Biomass values were comparatively low in all three subareas. Biomass was largest in Southern New England, intermediate in New York Bight, and smallest in Chesapeake Bight. Biomass ranged from 0.05 g/m to 1.4 g/m in Southern New England, from 0.003 g/m to 1.8 g/m in New York Bight, and from 0.07 g/m" to 0.6 g/m" in Chesapeake Bight. Generally, biomass was slightly larger in the broader range classes than in the narrower ones in each of the subareas. Nematoda were most widely distributed in South- ern New England and Chesapeake Bight, where they were found in all temperature ranges except one; in Southern New England, they were absent in the 20° +C class; and in Chesapeake Bight,they were ab- sent in the 8.0°%-11.9°C class. In New York Bight, they were found in only four of the classes: 0°%-3.9°C, 8.0°-11.9°C, 12.0°%-15.9°C, and 16.0°-19.9°C. Den- sities of nematodes were greatest in Southern New England (0.2/m to 27/m>), intermediate in Chesa- peake Bight (0.3/m> to 3.7/m>), and lowest in New York Bight (0.05/m* to 0.5/m*). The contribution of nematodes to biomass is quite small. Biomass in Southern New England ranged from 0.002 to 0.02 g/m; in New York Bight, from trace amounts to N180 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 40.-Mean number of individuals of each taxonomic group listed by temperature-range class, representing the Southern New England subarea [In number per square meter] Taxonomic group Range in bottom water temperature (°C) 0°-3. 39 4.0°-7 39 s.0°-11,99°- . 12.0°-15.99. . ig.09-10.9° -+20,.00-23.900 . 24100+ No . /m2 No . /m2 No . /m2 No . /m2 No. /m2 No . /m2 No. /m2 PORIFERA 0.13 1.57 1.67 - 0.36 0.57 7.50 COELENTERATA 3:12 29.86 14.00 16.88 $.03 40.28 275.80 Hydrozoa - 4.71 - 1.17 3.90 34.21 152.70 Anthozoa 3.12 25.14 14.00 15.71 1/13 6.07 123:10 Alcyonacea 0.66 1.57 2.17 1.52 - - - Zoantharia 0.91 22.86 10.83 12.75 0.94 5.00 1.00 Unidentified 1.54 0.71 1.00 1.44 0.19 1.07 122.10 PLATYHELMINTHES - - - 0.54 7.64 0.21 - Turbellaria - - - 0.54 7.64 0.21 - NEMERTEA 1.06 3.00 5.00 9.00 14.00 2.04 2.60 ASCHELMINTHES 1.46 0.71 0.92 3.94 26.90 0.18 - Nematoda 1.46 0.71 0.92 3.94 26.90 0.18 - ANNEL IDA 84.76 384.29 314.92 413.15 668.90 223.86 511.30 POGONOPHORA 5.15 - - - - - - SIPUNCUL IDA 6.46 21.00 8.83 7.94 18.19 1.89 15.20 ECHIURA 0.35 - - - - - - PRIAPUL IDA 0.13 - - - - - - MOLLUSCA 45.17 133.14 143.33 204.38 121.29 544.61 165.70 Polyplacophora 0.24 - 0.50 1.92 - 0.21 7.50 Gastropoda 5.70 1.43 2.17 15.50 30.94 174.36 44.80 Bivalvia 97 A1 127.14 123.42 184.92 90.36 369.50 113.40 Scaphopoda 2.13 3.86 2.93 - - 0.54 - Cephalopoda - 0.71 14.92 - - - - Unidentified - - - 2.04 - - - ARTHROPODA 11.20 95.28 93.50 1910.58 2226.74 1476.25 1221.90 Pycnogonida - - - 0.23 1.19 - 4.30 Arachnida - - - - - - - Crustacea 11.20 95.28 93.50 1910.34 2225.55 1476.25 1217.60 Ostracoda - - - 0.40 - 0.64 2.10 Cirripedia - - - 0.38 115.74 7.04 2.10 Copepoda 0.24 - - 0:12 - - - Nebaliacea - - - - - - - Cumacea 1.50 1.71 3.08 42.86 83.71 15.79 1.00 Tanaidacea 0.46 - - - - - - Isopoda 0.74 1.57 1.50 7.36 34.90 9.07 3.30 Amphipoda 8.06 92.00 88.08 1855.94 1986.68 1405.75 1192.80 Mysidacea - - - - - 4.96 1.10 Decapoda 0.20 - 0.83 3.27 4.52 33.00 15.20 BRYOZOA - - 0.42 0:21 65.03 68.32 97.90 BRACHIOPODA - - - - - - - ECHINODERMATA 7:59 92.28 358.58 195.56 31.22 9.78 3.30 Holothuroidea 2+43 5.29 4.25 12.1? 0.16 2.21 0.20 Echinoidea 0.17 1.57 2.25 15.21 27.00 6.46 - Ophiuroidea 4.85 84.57 349.00 165.15 0.16 1.00 2.70 Asteroidea 0.13 0.86 3.08 3.08 3.90 0.11 0.40 HEMICHORDATA 0.11 f 0.42 0.79 - - - CHORDATA 1.52 2.29 10.75 26.23 35.64 104.89 38.50 Ascidiacea 1.52 2.29 10.75 26.23 35.64 104.89 35.50 UNIDENTIFIED 5.83 5.29 7.33 8.14 13.87 2.00 14.00 only 0.003 g/m*; and in Chesapeake Bight, from trace amounts to 0.01 g/m. Annelida were found in all temperature classes in each of the subareas of the Middle Atlantic Bight region and were major contribtuors in both density and biomass of the overall macrobenthic fauna. Overall densities diminished slightly in a southerly direction through the subareas. Also, in the three subareas, slightly greater densities were found in the broader temperature-range groupings than in the narrower ones. Density values in Southern New England ranged from 85/m* in the narrowest class to in the 16.0°-19.9°C class. In the other classes, the average density ranged from greater than 200/m* to slightly more than In the New York Bight, lowest density was in the 0°%-8.9°C MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N181 TABLE 41.-Mean number of individuals of each taxonomic group listed by temperature-range class, representing the New York Bight subarea [In number per square meter] Taxonomic group Range in bottom water temperature (°C) 09-3. 99 4.0°-7.99 _ 8.09-11.99 12.0°-15.99 16.0°-19.99 20.00-23.9° 24.0°+ No . /m2 No . /m2 No. /m2 No. /m2 No . /m2 No . /m2 No. /m2 PORIFERA - - 0.25 1.17 - 0.67 3.00 COELENTERATA 4.64 9.00 4.75 4.64 5.06 19.35 - Hydrozoa 0.06 - 1.88 4.24 1.50 10.94 - Anthozoa 4.58 9.00 2.88 0.40 2,56 8.40 - Alcyonacea 1.83 7.00 0.94 - - - - Zoantharia 1.44 0.40 0.50 0.24 3.31 7.77 - Unidentified 1.31 1.60 1.44 0.17 0.25 0.64 - PLATYHELMINTHES - - - 0.24 0.04 - Turbellaria - - - 0.24 - 0.04 - NEMERTEA 0.17 2.00 1.25 3.52 3.78 3.43 3:25 ASCHELMINTHES 0.47 a 0.25 0.05 0.06 - - Nematoda 0.47 - 0.25 0.05 0.06 - - ANNEL IDA 40.33 196.60 102.00 277.40 147.06 961.90 700.00 POGONOPHORA 4.39 - - - - - - SIPUNCUL IDA 2.64 7.40 3.44 4.45 - - - ECHIURA 0.28 - - - - 0.46 - PRIAPUL IDA - - - - - - - MOLLUSCA 56.33 37.40 109.56 54.62 87.75 585.33 360.75 Polyplacophora 0.17 - 0.38 - - - - Gastropoda 10.58 1.20 25.56 5.86 3.38 56.56 6.25 Bivalvia 40.94 33.00 77.88 48.21 84.38 528.77 354.50 Scaphopoda 4.64 3.20 5.75 0.55 - - - Cephalopoda - - - - - - - Unidentified - - ~ - - - - ARTHROPODA 6.33 48.60 401.31 1023.31 582.97 439.71 347.25 Pycnogonida - - - - - 0.21 - Arachnida - - - - - 0.50 - Crustacea 6.33 48.60 401.31 1023.31 582.97 439.00 347.25 Ostracoda - - - - - 1.02 - Cirripedia - - - 0.07 - 250.77 - Copepoda - - 0.25 - - - - Nebaliacea 0.06 - - - - - - Cumacea 0.94 13.40 14.50 24.69 3.09 2.60 - Tanaidacea 0.11 - - - - - - Isopoda 0.53 2.80 4.88 12.14 25.66 10.08 3.00 Amphipoda 4.58 20.20 379.62 974.29 550.00 153.50 329.50 Mysidacea 0.06 - - 0.14 0.12 3.19 - Decapoda 0.06 12.20 2.06 11.98 4.09 17.85 14.75 BRYOZOA - - 10.56 2.74 0.12 10.23 25.50 BRACHIOPODA ~ > - - * - + ECHINODERMATA 4.39 18.20 81.75 16.90 35.66 109.94 31.50 Holothuroidea 1.78 - 1.81 0.40 0.06 0.94 - Echinoidea - 1.20 0.25 15.74 35.59 107.46 31.50 Ophiuroidea 2.56 15.40 76.19 0.38 - 0.54 - Asteroidea 0.06 1.60 3.50 0.38 - 1.00 - HEMICHORDATA - - - - - 0.25 - CHORDATA 1.17 0.80 0.12 16.38 6.97 1.10 - Ascidiacea 1.17 0.80 0.12 16.38 6.97 1.10 - UNIDENTIFIED 3.17 1.20 5.44 2.67 0.78 10.67 - class, where were found; in the 20.0°%-23.9°C class, a high of 962/m* were found. Another sig- nificantly high density was found in the broadest range class in this region, 700/m* in the 24.0°+C class. Considerably lower values were found in the other classes in this subarea, ranging from 102/m* to nearly 200/m*. Density values in Chesapeake Bight were lowest in the narrowest temperature | range (15.7/m>) and were highest (217/m>) in the 20.0°-283.9°C range. Two other classes contained densities greater than 100/m', the 8.0°%-11.9°C and the 24.0° +C, but less than 100/m>* were found in the 4.0°-7.9°C, 12.0°-15.9°C, and 16.0°-19.9°C classes. Biomass of annelids also diminished slightly to the south across the shelf and slope; greatest overall values were found in Southern New England, where N182 TABLE 42.-Mean ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES number of individuals of each taxonomic group listed by temperature-range class, representing the Chesapeake Bight subarea [In number per square meter] Taxonomic group Range in bottom water temperature (0C) y9-3.9° 4.00-7.909°. s:09-11.99°~ 16.00-19-99 . p0.o0-03.0° _ 21 :0°+ No. /m2 No.. /m2 No. /m2 No . /m2 No . /m2 No. /m2 No . /m2 PORIFERA 0.07 - - - - 0.61 0.59 COELENTERATA 3.36 3.80 18.00 124.50 20.69 6.99 15.78 Hydrozoa - - 14.80 122.50 18.62 4.66 3.00 Anthozoa 3.36 3.80 3.20 2.00 2.06 2.32 12.80 Alcyonacea 0.82 - - - - - - Zoantharia - - - - 0.38 1.28 5.32 Unidentified 2.54 3.80 3.20 2.00 1.69 1.04 7.48 PLATYHELMINTHES ~- - 3.00 - 0.25 0.34 0.57 Turbellaria - - 3.00 - 0.25 0.34 0.57 NEMERTEA 0.79 3.40 1.40 2:2 2.75 8.85 3.06 ASCHELMINTHES 1.29 0.80 - 0.25 0.94 0.77 3.65 Nematoda 1.29 0.80 - 0.25 0.94 0.77 3.65 ANNEL IDA 15.71 73.60 162.60 69.38 97.69 216.55 197.52 POGONOPHORA 6.21 4.40 15.40 50.38 - 0.08 - SIPUNCUL IDA 2.18 1.20 - 2.88 0.25 0.24 - ECHIURA 0.43 - - - - 0.31 - PRIAPUL IDA 0.07 - - - - - - MOLLUSCA 36.63 502.00 168.80 395.50 148.88 1114.54 473.80 Polyplacophora 1.14 - 0.40 - - - 0.20 Gastropoda 3.61 8.20 4.00 8.50 1.06 86.78 36.46 Bivalvia 29.89 488.40 162.60 372.88 147.19 1027.32 437.13 Scaphopoda 1.98 5.40 1.80 14.12 0.62 0.43 - Cephalopoda - - - - ~ - - Unidentified - - - - - - - ARTHROPODA 2.04 13.62 631.40 85.09 101.88 279.11 319.37 Pycnogonida = - - - 1.00 0.70 2.46 Arachnida - - - - - ~ - Crustacea 2.04 13.62 631.40 85.09 100.88 278.40 316.91 Ostracoda 0.21 - - - - 0.03 0.04 Cirripedia - - - - - 0.47 - Copepoda i - - - - - - Nebaliacea - - - - 0.25 0.03 - Cumacea 0.14 4.40 29.40 8.84 4.44 21.55 113 Tanaidacea 0.29 - f - - - - Isopoda 0.21 0.40 6.40 3.88 12.88 28.70 13.68 Amphipoda 1.18 8.42 589.20 71.38 81.06 216.03 288.74 Mysidacea - - - - - 5.40 6.11 Decapoda - 0.40 6.40 1.00 2.25 6.19 7-20 BRYOZOA - - - 7.88 8.00 11.40 - BRACHIOPODA - - - - 0.12 - - ECHINODERMATA 3.32 9.20 4.60 103.12 14.12 44.14 5.30 Holothuroidea 0.36 7.60 a 10.00 0.38 0.20 0.06 Echinoidea - - 1.40 2.50 10.06 43.36 4.09 Ophiuroidea 2.61 1.60 2.80 90.12 3.19 0.50 1.07 Asteroidea 0.36 - 0.40 0.50 0.50 0.07 0.07 HEMICHORDATA - - - - - 0.15 - CHORDATA 0.96 - - 2.75 1.88 0.65 21.35 Ascidiacea 0.96 - - 2:75 1.88 0.65 21.35 UNIDENTIFIED 3.39 - 0.80 11.00 0.38 7.38 20.13 the range of biomass was from 2.1 to 37 g/m in the extremes of the temperature ranges. In Southern New England, biomass tended to increase as tem- perature range broadened. In New York Bight, bio- mass distribution of annelids was somewhat similar to that in Southern New England; the smallest bio- masses (3 g/m) were found in the narrowest class and largest (30 g/m) in the broadest class. Annelid biomass in Chesapeake Bight ranged from 2 g/m in the narrowest class to 15 g/m in the broadest. Bio- masses between 3 and 11 g/m* were found in the other classes. Pogonophora definitely preferred the southern- most reaches of the Middle Atlantic Bight region, and were most abundant in Chesapeake Bight in both density and biomass. In each of the other two MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N183 TABLE 48.-Mean biomass of each taxonomic group listed by temperature-range class, representing the Southern New England subarea [In grams per square meter] Taxonomic group Range in bottom water temperature (0C) 090-3. 99 4,.99-7,.99 8.0°-11.99 12.0°-15.98 16.0°-193.99 20.0°-23.99 24.0°+ 2 2 2 2 2 2 2 g/m g/m g/m g/m g/m g/m g/m PORIFERA 0.029 0.084 0.085 - 0.416 0.023 0.450 COELENTERATA 0.563 2.869 30.689 4.564 9.337 6.140 7.257 Hydrozoa - 0.163 - 0.102 0.267 2.079 4.314 Anthozoa 0.563 2.706 30.689 3.544 0.070 4.061 2.943 Alcyonacea 0.042 0.039 0.442 0.446 a - - Zoantharia 6.321 2.660 30.185 2.900 0.050 3.992 0.350 Unidentified 0.200 0.007 0.062 0.198 0.020 0.069 2.593 PLATYHELMINTHES - - - 0.018 0.041 0.003 - Turbellaria - - - 0.018 0.041 0.003 - NEMERTEA 0.046 0.219 0.961 0.965 1.423 1.134 0.406 ASCHELMINTHES 0.007 0.007 0.004 0.007 0.015 0.002 l Nematoda 0.007 0.007 0.004 0.007 0.015 0.002 - ANNEL IDA 2.069 9.734 9.136 29.241 24.401 22.209 37.169 POGONOPHORA 0.038 - - - - - - SIPUNCULIDA 2.534 0.804 0.366 1.231 1.388 0.021 2.052 ECHIURA 0.206 - - - - - ~- PRIAPULIDA 0.086 - - - - - - MOL LUSCA 0.669 3.586 4.521 85.263 279.812 86.146 926.886 Polyplacophora 0.003 - 0.005 0.028 - 0.024 747285 Gastropoda 0.042 0.014 0.018 8.496 1.791 4.407 2.592 Bivalvia 0.596 3.479 4.256 76.731 278.021 81.710 916.569 Scaphopoda 0.028 0.086 0.038 - - 0.005 - Cephalopoda - 0.007 0.204 - - - - Unidentified - - - 0.008 ~ - - ARTHROPODA 0.082 0.465 0. 342 9.312 64.580 11.604 10.654 Pycnogonida - - - 0.002 0.002 - 0.021 Arachnida - - - - - - - Crustacea 0.082 0.465 0. 342 9.310 64.578 11.604 10.633 Ostracoda - - - 0.002 - 0.006 0.021 Cirripedia - - - 0.008 43.464 0.603 0.043 Copepoda 0.002 - - <0.001 - - - Nebaliacea - - - - - - - Cumacea 0.015 0.017 0.021 0.276 0.258 0.054 0.010 Tanaidacea 0.004 - - - - - - Isopoda 0.020 0.179 0.101 0.212 0.728 0.112 0.035 Amphipoda 0.037 0.269 0.212 8.574 18.260 6.933 9.417 Mysidacea - ~ - - - 0.013 0.125 Decapoda 0.004 - 0.008 0.238 1.868 3. 883 0.982 BRYOZOA - - 0.004 0.046 2.357 2.284 2.698 BRACKIOPODA - - - - - - - ECHINODERMATA 3.280 49.097 56.991 54.862 30. 305 2.707 2.698 Holothuroidea 2.332 5.864 2.674 37.909 14.702 0.115 0.031 Echinoidea 0.262 25.983 27.111 2.378 15.497 2.374 - Ophiuroidea 0.656 17.241 25.008 7.465 0.002 0.057 1.709 Asteroidea 0.030 0.009 2.198 7.110 0.104 0.161 0.958 HEMI 0.001 - 0.126 0.150 - - - CHORDATA 0.148 0.097 1.418 3.137 3.850 23.102 22.993 Ascidacea 0.148 0.097 1.418 3.137 3.850 23.102 22.993 UNIDENTIFIED 0.183 0.280 0.101 0.684 0.261 0.880 0.280 subareas, they were found only in the narrowest temperature-range class. Density of pogonophorans was 5/m> in Southern New England and was 4/m in New York Bight. Highest densities were found in Chesapeake Bight, where average densities ranged from 4/m? in the 4.0°%-7.9°C class to in the midpoint class of 12.0°%-15.9°C. In the 0°-8.9°C and the 8.0°-11.9°C classes, density values were 6/m' N184 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES TABLE 44.-Mean biomass of each taxonomic group listed by temperature-range class, representing the New York Bight subarea [In grams per square meter] Range in bottom water temperature (°C) Taxonomic group go-s:.g0 s.0°-11.90 - 12.00-185.09. 16.0°-19.90. 20.00-25.99° - 2a.0°+ 2 2 2 2 2 2 2 g/m g/m g/m g/m g/m g/m g/m PORIFERA - - 0.004 0.106 - 0.007 0.030 COELENTERATA 0.563 0.572 3.944 6.223 0.381 2.909 - Hydrozoa <0. 001 - 0.016 0.030 0.029 0.184 - Anthozoa 0.563 0.572 3.928 0.193 0. 352 2.726 - Alcyonacea 0.154 0. 362 0.284 - - - - Zoantharia 0.243 0.004 3.429 0.180 0.318 2.628 ~- Unidentified 0.166 0.206 0.215 0.013 0.034 0.097 - PLATYHELMINTHES - ~ - 0.009 - 0.002 - Turbellaria - - - 0.009 - 0.002 - NEMERTEA 0.003 0.138 0.081 0.264 0.920 1.839 0.065 ASCHELMINTHES 0.003 - 0.002 <0. 001 <0. 001 - - Nematoda 0.003 - 0.002 <0. 001 <0. 001 - - ANNEL IDA S.277 5.290 5.452 11.390 6.523 29.611 11.482 POGONOPHORA 0.023 - - - - - - SIPUNCULIDA 0.279 0.714 0.081 1.089 - - - ECHIURA 0. 800 - - - - 0.459 - PRIAPUL IDA - - - - - - - MOLLUSCA 0.886 1.032 65.235 104.818 77.520 604.364 373.000 Polyplacophora 0.004 - 0.004 - - - - Gastropoda 0.115 0.020 0.099 1.284 0.208 6.652 6.875 Bivalvia 0.679 0.974 65.049 103.522 77.312 597.712 366.125 Scaphopoda 0.088 C. 038 0.083 0.012 - - - Cephalopoda - - - - - - - Unidentified ~ - - - - - ~- ARTHROPODA 0.094 1.460 2.379 7.436 5.139 21.060 1.327 Pycnogon ida - - - - - 0.004 - Arachnida - - - - ~ 0.002 - Crustacea 0.094 1.460 2.379 7.435 5.139 21.054 1.327 Ostracoda - - - - - 0.009 - Cirripedia - - - <0. 001 - 14.308 - Copepoda - - 0.001 =- - = = Nebaliacea <0.001 - - - - - =- Cumacea 0.008 0.088 0.076 0.115 0.020 0.019 - Tanaidacea 0.001 - - - - - - Isopoda 0.018 0.016 0. 348 0.422 0.785 0.336 0.030 Amphipoda 0.038 0.060 1.872 4.565 3.843 2.445 0.715 Mysidacea <0. 001 - - 0.004 0.001 0.015 - Decapoda 0.028 1.296 0.082 2.329 0.490 3.922 0.582 BRYOZOA - - 0.146 0.012 0.001 0.305 0.128 BRACKHIOPODA - - - - - - - ECHINODERMATA 2.227 9.336 24.745 16.669 70.033 42.436 5.582 Holothuroidea 1.456 - 0.599 0.496 0.218 0.116 - Echinoidea - 5.688 6.686 13.105 69.815 36.202 5.582 Cphiuroidea 0.702 2.238 2.879 0.006 - 0.385 - Asteroidea 0.069 1.410 14.581 3.062 - 5.733 - HEMICHORDATA - - - - - 0.020 - CHORDATA 0.182 0.104 0.024 1.061 0.226 0.083 - Ascidiacea 0.182 0.104 0.024 1.061 0.226 0.083 - UNIDENTIFIED 0.113 0.816 0.073 0.192 0.411 0.363 - and 15/m, respectively. The biomass of pogonopho- rans in Southern New England was 0.04 g/m and in New York Bight was 0.02 g/m. In Chesapeake Bight, biomass ranged from trace amounts in the 20.0°-23.9°C class to 0.4 g/m" in the 12.0°-15.9°C class. In the narrower classes, biomass ranged from 0.02 to 0.08 g/m. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N185 TABLE 45.-Mean biomass of each taxonomic group listed by temperature-range class, representing the Chesapeake Bight subarea [In grams per square meter] Range in bottom water temperature (°C) Taxonomic group 00-3. 99 4.0°-7.99 8.0°-11.99° 12.0°-15.9° 16.0°-19.99° 20.00-23.9° 24.0°+ g/m2 g/m2 g/m2 PQRIFERA 0.022 - ~- COELENTERATA 0.457 0.092 0.138 Hydrozoa - - 0.038 Anthozoa 0.457 0.092 0.100 Alcyonacea 0. 304 - = Zoantharia - - - Unidentified 0.153 0.092 0.100 PLATYHELMINTHES - - 0.030 Turbellaria ~ - 0.030 NEMERTEA 0.198 0.134 0.442 ASCHELMINTHES 0.009 0.004 - Nematoda 0.009 0.004 - ANNELIDA 2.415 10.114 11.968 POGONOPHORA 0.016 0.026 0.034 SIPUNCULIDA 2.460 0.164 ~ ECHIURA 2.544 - - PRIAPULIDA 0.036 - - MOLLUSCA 0. 386 2.448 74.814 Polyplacophora 0.010 - 0.004 Gastropoda 0.091 0.066 0.030 Bivalvia 0.268 2.334 74.740 Scaphopoda 0.017 0.048 0.040 Cephalopoda - - - Unidentified - ~ - ARTHROPODA 0.011 0.162 3.354 Pycnogonida - - - Arachnida - - - Crustacea 0.011 0.162 3. 354 Ostracoda 0.001 - - Cirripedia ~ - ~ Copepoda - - - Nebaliacea - - - Cumacea 0.001 0.044 0.150 Tanaidacea 0.001 - = Isopoda 0.002 0.004 0.064 Amphipoda 0.006 0.030 3.014 Mysidacea - - - Decapoda - 0.084 0.126 BRYZOA - - - BRACKHIOPODA - - - ECHINODERMATA 1.951 10.514 0.178 Holothuroidea 1.015 10.356 - Echinoidea - - 0.132 Ophiuroidea 0.930 0.158 0.038 Asteroidea 0.006 - 0.008 HEMICHORDATA -o. - - CHORDATA 0.071 - - Ascidiacea 0.071 - - UNIDENTIFIED 0.058 - 0.004 g/m g/m? g/m? g/m2 - - 0.085 0.002 0.283 0.877 1.389 7.857 0.114 0.163 0.050 0.574 0.169 0.714 1.339 7.283 - 0.116 1.216 7.267 0.169 0.598 0.123 0.016 - 0.013 0.007 0.007 - 0.013 0.007 0.007 0.606 0.072 0.398 0.389 0.002 0.004 <0.001 0.014 0.002 0.004 <0.001 0.014 5.719 3.453 8.442 15.287 0.416 ~ <0.001 - 0.075 0.009 0.031 - - - 0.093 o 102.282 40.568 47.532 101.399 - - - 0.016 0.066 0.136 6.605 2.805 101.804 40.428 40.921 98.578 0.412 0.004 0.006 - 0.744 1.501 3.374 4.029 - 0.004 0.003 0.016 0.744 1.497 3.371 4.013 - - <0.001 <0.001 - - 0.007 - - 0.001 <0.001 i 0.032 0.019 0.065 0.005 0.248 1.003 0.355 0.216 0.454 0.412 2.329 1.642 - - 0.020 0.019 0.010 0.063 0.594 2.130 0.034 0.022 0.286 - - 0.001 - - 26.493 21.229 15.801 4.193 23.266 0.094 0.743 0.054 0.849 20.504 15.012 4.057 1.966 0.082 0.040 0.082 0.412 0.549 0.006 <0.001 - - 0.078 ~ 0.074 0.093 0.268 15.254 0.074 0.093 0.268 15.254 0.274 0.008 0.058 0. 322 Sipunculida were ubiquitous in Southern New | England but not in the other two subareas. In New York Bight, they were present only in the first four classes, but in Chesapeake Bight they were present in all but two of the classes, the 8.0°%-11.9°C and 24.0°+C classes. Overall, in each of the three sub- areas, sipunculid density was moderate. In Southern New England, density values ranged from 2/m" to 21/m"; in New York Bight, substantially lower quantities ranged from 3/m> to 7/m*; in Chesapeake Bight, even lower values were found, from to 3/m'. Biomass distribution was essentially similar N186 to that of density among the subareas-largest in Southern New England, intermediate in Chesapeake Bight, and smallest in New York Bight. Biomass ranged from 0.02 to 3 g/m in Southern New Eng- land, 0.08 to 1 g/m" in New York Bight, and 0.009 to 3 g/m in Chesapeake Bight. No definite relation- ship was discernible between biomass and tempera- ture range. Echiura were not common in any of the subareas of the Middle Atlantic Bight region and were found in only the narrowest temperature class in Southern New England (0.3/m* weighing 0.2 g/m?). In New York Bight, they were found in only two classes- the narrowest, where density was 0.3/m* and bio- mass 0.8 g/m, and in the 20.0°%-23.9° class where density was and biomass, 0.5 g/m. In Chesa- peake Bight, they were present in the same two classes and in roughly the same magnitudes; 0.4/m weighing 2.5 g/m in the narrowest class and 0.3/m* weighing 0.09 g/m in the broader class. Priapulida were neither broadly distributed nor plentiful in any of the subareas. They were present in only the narrowest temperature range in both Southern New England and Chesapeake Bight, and were absent entirely in the New York Bight. Mollusca were recorded in all temperature classes in each of the subareas of the Middle Atlantic Bight region. As a group, mollusks were most abundant in Chesapeake Bight; Southern New England was see- ond, followed by New York Bight. Because mollusks are made up of several subcomponents, a detailed analysis will be found among the several contrib- utors to the total molluscan fauna. Polyplacophora were more plentiful in Southern New England than in the other two subareas. In Southern New England, they were found in five tem- perature classes; in New York Bight, two classes; and in Chesapeake Bight, three classes. In Southern New England, the trend of increasing density as temperature range broadened was discernible. The highest density (8/m*) occurred in the broadest class, and the lowest (0.2/m?) in the narrowest, 0°-3.9°C, as well as in the 20.0%-28.9°C class. In New York Bight, in the 0°%-8.9°C and 8.0%-11.9°C classes, polyplacophoran densities were 0.2/m* and 0.4/m?, respectively, but in Chesapeake Bight their density ranged from 0.2/m* to and tended to increase as temperature range narrowed. Where ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES they were found in Chesapeake Bight, the lowest density was in 20.0°%-23.9°C class and the highest density in the narrowest temperature range. Chiton biomass in the Southern New England subarea tended to follow the pattern established for density, and the smallest biomass (0.003 g/m?) was found in the narrowest range, and the largest biomass (8 g/m) in the broadest range. In New York Bight, in both classes in which chitons occurred, the biomass was similar, 0.004 g/m". Chiton biomasses in Chesa- peake Bight were nearly identical in the narrowest class (0.01 g/m>) and in the broadest (0.02 g/m). In midrange, the biomass was 0.004 g/m. Gastropoda were found in all temperature-range classes in each of the subareas. Both density and biomass tended to decrease as latitude decreased; greatest values for both were found in Southern New England, intermediate values in New York Bight, and lowest in Chesapeake Bight. No definite rela- tionships was discernible between density and tem- perature range in any of the subareas. Gastropod density ranged from 1/m? in the 4.0°-7.9°C class to 174/m' in 20.0°-23.9°C in Southern New England, where generally lower densities occurred in the nar- rower ranges and higher densities in the broader ranges (see table 40). In New York Bight, gastropod density ranged from 1/m* in the 4.0°%-7.9°C class to 57/m> in 20.0°-23.9°C. Here, moderately high den- sity values occurred at both ends of the temperature- range spectrum. Density values in Chesapeake Bight ranged from 1/m* in the 16.0°-19.9°C class to in the adjacent class, 20.0°%-23.9°C. Intermediate values, tending on the lower side, were found in the other classes. Overall gastropod biomass values were comparatively low, and in Southern New England ranged from 0.01 g/m? in the 4.0°%-7.9°C and 8.0°- 11.9°C classes to 9 g/m" in 12.0°%-15.9°C. In New York Bight, gastropod biomass ranged from 0.02 g/m in the 4.0°-7.9°C class to 7 g/m" in the two broadest classes. Biomasses of 1 g/m or less were found in the other classes. In Chesapeake Bight, which contained the smallest biomass of gastropods, values ranged from 0.08 g/m" in the 8.0%-11.9°C class, to 7 g/m" in 20.0°-23.9°C. In only one other class, 24.0° +C, were biomasses of more than 2 g/m." Values in all other classes were below 1 g/m. Bivalvia were the largest contributors of mollus- can abundance and occurred in all temperature- range classes in each of the subareas of the Middle Atlantic Bight region. Greatest overall densities of MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION bivalves were found in Chesapeake Bight and South- ern New England. The single largest average den- sity occurred in the 20.0°%-283.9°C class in Chesa- peake Bight, where 1,027/m>* were found. The next highest density occurred in the same class in the New York Bight. However, in this subarea, other density values were below those of similar classes in either of the two other subareas. In Southern New England, bivalve density ranged from 37/m* in the 0°-3.9°C class to 370/m° in 20.0%-283.9°C. Values below 100/m* occurred in the 16.0°-19.9°C class, but in all other classes density values were between 100/m* and 200/m*. In New York Bight, which con- tained the lowest overall values, density exceeded in only the two broadest classes, the previ- ously mentioned high of 528/m> in the 20.0°-23.9°C class and 354/m> in 24.0°+C. Density values rang- ing from 33/m' to 84/m' occurred in the other classes in New York Bight. The density of bivalves in Chesapeake Bight was 30/m* in 0°-3.9°C and, in all other classes, was more than 100/m?; 147/m" and 168/m" occurred in the 16.0°-19.9°C and 8.0°%-11.9°C classes, respectively, and more than 370/m> in the re- maining three classes. A considerably different pic- ture unfolds when considering biomass among the three subareas in the Middle Atlantic Bight region. New York Bight, on the whole, had a higher biomass than any of the other two subareas; Southern New England was second. The biomass in Chesapeake Bight, notwithstanding its leadership in density, was lowest among the three subareas. Average biomass in Southern New England ranged from 0.6 g/m" in the 0°-3.9°C class to 917 g/m? in the broadest, the 24.0°+C, class. In Southern New England, the tendency was that biomass increased as temperature range broadened, but the actual values were widely divergent. In New York Bight, average bivalve bio- mass ranged from 0.7 g/m: to 597 g/m: in the 0°~-8.9°C class and the 20.0°-28.9°C class, respec- tively. However, a greater part of the remaining classes contained values that were about 100 g/m or more, whereas in Southern New England, the tendency was for considerably smaller biomasses to occur. The biomass of bivalves in Chesapeake Bight ranged from 0.3 g/m" in the 0°-3.9°C class to 102 g/m? in the 12.0°%-15.9°C class. The remaining classes contained less than 100 g/m. Scaphopoda were most prevalent in Chesapeake Bight and were absent only in the broadest class. In New York Bight, they occupied the narrower to midrange classes and were absent from the broader range classes (16.0°-24.0°+C); in Southern New England, Scaphopoda occupied the three narrower N187 range classes (0°-11.9°C), were absent in the next two between 12.0° and 19.9°C, were present in the 20.0°-23.9°C range, and absent in the broadest range, 24.0°+C. Density values were highest in Chesapeake Bight, where mean densities ranged from 0.4/m' to 14/m'. In New York Bight, where densities were between those of the other two sub- areas, the range of density was from 0.6/m* to 6/m*. Scaphopod densities in Southern New England ranged from 0.5/m* to 4/m*. On the whole, seapho- pod biomass values were largest in the Chesapeake Bight subarea. Biomass ranged from 0.004 g/m" to 0.4 g/m. In New York Bight, biomass values ranged from 0.01 g/m" to 0.08 g/m*. The biomass of tusk shells in Southern New England was somewhat com- parable to that in the New York Bight. Smallest biomass was 0.005 g/m in the 20.0°-23.9°C class; in the other three classes in which tusk shells were present in Southern New England, values ranged between 0.03 and 0.09 g/m*. Cephalopoda were found only in Southern New England and only in the 4.0°-7.9°C and the 8.0°- 11.9°C classes. Density values were high, 0.7/m* and in the two classes, respectively, whereas bio- mass values were comparatively lower, 0.007 and 0.2 g/m. Arthropoda density and biomass values are sum- mations of the subcomponents of this phylum and are reflected in the crustacean abundances given below. Pycnogonida occurred in each of the subareas of the Middle Atlantic Bight region, but were restricted in each of them to only a relatively few temperature classes. In Southern New England, pycnogonids occurred in three classes, the 12.0°%-15.9°, the 16.0°- 19.9°, and the 24.0°+C; in New York Bight, they were found only in the 20.0°-23.9°C class; and in Chesapeake Bight, were found in the three broad- range categories between 16.0°+, and 24.0°+C. Overall density was highest in Southern New Eng- land and ranged from 0.2/m> to 4/m?, lowest in New York Bight where only 0.2/m> was found, and inter- mediate in Chesapeake Bight where the range was from 0.7/m' to 3/m*. Pyenogonid biomass was on the whole quite low, in Southern New England the range of biomass was from 0.002 to 0.02 g/m". In New York Bight, 0.004 g/m was found and in Chesapeake Bight, the range was from 0.008 to 0.02 g/m. Arachnida were very sparsely distributed, oc- curring only in the New York Bight subarea and in only one temperature class, 20.0°-23.9°C. Density was 0.5/m* and biomass, 0.002 g/m. N188 Crustacea were major contributors to the macro- fauna in the Middle Atlantic Bight region, occurring in all temperature-range classes in each of the sub- areas. Generally, both density and biomass dimin- ished to the south, so that abundance was greatest in Southern New England, intermediate in New York Bight, and lowest in Chesapeake Bight. In Southern New England, crustacean densities were highest in the midrange classes and less in both narrowing and broadening temperature ranges, although substantial densities occurred in the latter. The range of density in Southern New England was from 11/m to 2,226/m*. In the three broadest classes (from 12°C to 24°+C), density values in Southern New England were more than 1,000/m*, whereas in the narrower classes they were below 100/m*. In the New York Bight, essentially the same conditions prevailed and lowest density (6/m*) was in the narrowest class, and in the 12.0°-15.9°C class,. In the classes between 8°C and 24° +C, exclud- ing 12.0°%-15.9°C, density values were betwen 300/m* and Crustacean density in Chesapeake Bight ranged from 2/m" in the narrowest class to 631/m> in the 8.0°%-11.9°C class. Crustacean biomass and density were similar in that largest amounts occurred in Southern New England, intermediate in New York Bight, and lowest in Chesapeake Bight. Biomass ranged from 0.08 g/m in 0°-3.9°C, to 65 g/m in 16.0°-19.9°C in Southern New England; somewhat smaller biomasses (10/m*-11/m') were found in the two broadest classes, but they dimin- ished sharply as temperature range narrowed. In New York Bight, essentially the same conditions prevailed where biomass increased as temperature range broadened. The smallest biomass occurred in the 0°%-3.9°C class with 0.09 g/m", and largest, 21 g/m, in the 20.0°-23.9°C class. The 24.0°+C class biomass dropped, significantly, to 1 g/m". In the remaining classes, biomass varied from 1 to 7 g/m. The crustacean biomass in Chesapeake Bight was moderately small and ranged from 0.01 g/m? in the narrowest class to 4 g/m? in 24.0° +C. Values of less than 1 g/m were found in the 4.0°-7.9° and the 12.0°-15.9°C classes and ranged from 2 to 3 g/m in the other three classes. Ostracoda were found in each of the subareas in rather limited distribution. In Southern New Eng- land, they occurred in only three temperature classes, the two broadest and the midpoint categories; in New Bight, they were relegated to one temperature class, 20.0°-23.9°C; and in Chesapeake Bight, they were found in the two broadest classes. As in other groups, greatest densities and biomasses occurred in ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES Southern New England. The values of biomass and density were relatively low, especially in Chesapeake Bight where only traces of biomass and very low values in density were found. Cirripedia, although not widely distributed among temperature ranges, contained significant amounts in both density and biomass, especially in Southern New England and New York Bight. In Southern New England, barnacles were found in temperature ranges from 12.0°-24.0°+C, but were relegated to two classes in New York Bight, 12.0°%-15.9°C and the 20.0°-28.9°C; in Chesapeake Bight, they oc- curred only in the 20.0°%-23.9°C class where both density and biomass were low. The highest in- dividual density of barnacles (251/m>) was found in New York Bight in the 20.0°%-28.9° class. In the 12.0°-15.9°C class, however, the density values were quite low (0.07/m>). In Southern New England, densities ranged from 0.4/m> to 116/m> in the 12.0°- 15.9°C and the 16.0-19.9°C classes, respectively. Lower values occurred in the two broadest classes where the density ranged from and 7/m'. Southern New England contained the single largest biomass of barnacles, 43 g/m" in the 16.0°-19.9°C class. In the remaining three classes, less than 1 g/m were found. In New York Bight, 14 g/m" of barnacles were recorded in 20.0°-23.9°C, and only trace amounts were found in 12.0°-15.9°C. Copepoda did not contribute greatly to the total macrofauna of the Middle Atlantic Bight region and were sparsely distributed in only two subareas. In Southern New England, copepoda were found in the narrowest temperature-range class and in the 12.0°- 15.9°C class in low densities and small biomasses. In New York Bight, they were relegated in low abun- dance to one class, 8.0°%-11.9°C. Nebaliacea were present only in New York Bight and Chesapeake Bight in low abundances. In New York Bight, they were found only in the 0°-3.9°C class where density was 0.06/m* and biomass was trace amounts. In Chesapeake Bight, they occurred in two classes, 16.0°-19.9°C and 20.0°%-23.9°C, where densities of 0.25/m* and 0.03/m* and biomasses of 0.001 and <0.001 g/m were found. Cumacea were present in all temperature classes in both Southern New England and Chesapeake Bight subareas, but were absent from the 24.0°+C class in New York Bight. Density values in each of the three subareas were moderate to moderately high, whereas biomass values were moderate to moderately low. On the whole, cumaceans favored the middle temperature ranges, and in Southern New England, the average density ranged from 1/m" to MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION 84/m>*. Densities in New York Bight were lower than they were in Southern New England and ranged from 0.9/m* to 25/m*'. In Chesapeake Bight, density ranged from 0.1/m* to Biomass of cumaceans was greatest in Southern New England and tapered off to the south. The average biomass in Southern New England ranged from 0.01 g/m to 3 g/m". In New York Bight, the smallest biomass was 0.01 g/m" and the largest was 0.1 g/m*. In Chesapeake Bight, which contained the lowest biomass of cuma- ceans, the range was between 0.001 g/m and 0.2 g/m. Tanaidacea were restricted to the narrowest range class in each of the three subareas of the Middle Atlantic Bight region. Greatest abundance was found in Southern New England, the next greatest in Chesapeake Bight, and lowest in New York Bight. Densities (maximum 0.46/m*) and bio- mass (maximum 0.004 g/m*') were low in all sub- areas. Isopoda occurred in all of the temperature-range classes throughout the Middle Atlantic Bight region, and greatest abundance was in Southern New Eng- land, next highest in Chesapeake Bight, and lowest in New York Bight. Densities of isopods in Southern New England ranged from 0.07/m to Values of density on either side of the midtemperature range diminished significantly, more so in the nar- rower ranges than in the broader ones. In New York Bight, the range of density values was from 0.5/m* to 26/m*. Density also decreased as tempera- ture range narrowed. In Chesapeake Bight, the same trends prevailed. The lowest density was 0.2/m* and the highest was 29/m*. The largest overall biomass values occurred in Chesapeake Bight, second largest in Southern New England, and smallest in New York Bight. The largest biomass was recorded in the 16.0°%-19.9°C class in Chesapeake Bight, where 1 g/m of organisms was found. The smallest bio- mass in this subarea was found in the 0°%-3.9°C class (only 0.002 g/m). In the New York Bight, the smallest biomass (0.02 g/m?) occurred in 0°-3.9°C and 4.0°-7.9°C. The largest biomass in this subarea (0.8 g/m') occurred in the 16.0°%-19.9°C class. In Southern New England, as in other areas, the small- est biomass (0.02 g/m?) was recorded in the 0°-3.9°C class. The largest biomass of isopods in Southern New England was present in 16.0°-19.9°C, where 0.7 g/m" was found. Amphipoda were found in all temperature ranges in each of the subareas; and, especially in density, amphipods were the single most numerous group N189 among the crustaceans. Southern New England had highest densities of amphipods, followed by New York Bight and Chesapeake Bight. The density values in Southern New England ranged from 8/m* in the narrowest temperature class to 1,987/m> in the 16.0°-19.9°C class. In Southern New England, the broader classes contained considerably higher densities of amphipods than did the narrower classes. Densities in the New York Bight ranged from 5/m in 0°-3.9°C to 974/m> in the 12.0°-15.9°C class. Den- sities in other classes ranged from 20/m* to 379/m*. The density of amphipods in Chesapeake Bight was lowest in 0°-3.9°C, where 1/m* was found, and highest in 8.0°-11.9°C where 589/m*> were found. Although amphipod biomasses were moderately high, they did not contribute as significantly to overall faunal abundance as did their densities. In Southern New England, biomass ranged from 0.04 g/m in 0°~-8.9°C to 18 g/m" in 16.0%19.9°C. In Southern New England, larger biomasses, as well as greater densities, were found in the broader range classes. Biomass in New York Bight ranged from 0.4 g/m in the narrowest class to 5 g/m" in the 12.0°-15.9°C class. In classes, Amphipod biomass was lower in Chesapeake Bight than in the other two subareas and ranged from 0.006 g/m" in the narrowest to 3 g/m in the 8.0°-11.9°C class. Biomasses greater than 1 g/m occurred in only two other classes, 20.0°-23.9°C, and 24.0° +C. In the remaining classes, biomasses were less than 1 g/m. Mysidacea occurrence in each of the subareas was confined generally to the broader temperature ranges. In Southern New England, they occurred in only the two broadest ranges; in New York Bight, they occurred in four temperature classes: 0°-3.9°, 12:0°>15.9°C, ~16.0°%19.9°C, and 20.0°-28.9°C; - in Chesapeake Bight, as in Southern New England, they were in the two broadest classes. Mysid density in Southern New England was moderately high, 1/m' to 5/m>. In New York Bight, density was 0.06/m* in the narrowest class, and in the remaining three classes averaged from in the two nar- rower classes to 3/m* in the broadest. In Chesapeake Bight, mysid density in the two broadest classes was and 6/m*. The biomass of mysids was mod- erately low in all subareas, and, in Southern New England, in the two classes in which they occurred, was 0.01 and 0.1 g/m'. In New York Bight, the smallest biomass was found in the narrowest class, where only trace amounts were found; in the remain- ing three classes, it ranged from 0.001 to 0.02 g/m. In Chesapeake Bight, moderately small biomasses (0.02g/m*) occurred in the two broadest classes. N190 Decapoda were found in all temperature ranges only in New York Bight; in both Southern New Eng- land and Chesapeake Bight, they were absent in one class. Average densities were moderately high in all subareas; overall densities were highest in Southern New England, next highest in New York Bight, and lowest in Chesapeake Bight. Decapod density in Southern New England ranged from 0.2/m' to 33/m>. In the New York Bight subarea, lowest den- sity was 0.06/m*, and highest was 18/m*. Chesa- peake Bight density ranged from 0.4/m' to 7/m'. Biomass was highest in the New York Bight subarea; smallest biomass, 0.03 g/m, occurred in the nar- rowest class, and largest biomass, 4 g/m", occurred in the 20.0°%-23.9°C class. In Southern New England, biomass ranged from 0.004 to 4 g/m. In Chesapeake Bight, smallest biomass, 0.01 g/m, was found in the 12.0°-15.9°C class, and largest biomass, 2.1 g/m, in 24.0° +C. Bryozoa were present in five temperature classes between 8.0° and 24.0°C in both Southern New Eng- land and New York Bight. In Chesapeake Bight, they were present in three of the classes between 12.0° and 23.9°C. Densities decreasd to the south. Densities in Southern New England tended to in- crease as temperature range broadened; highest den- sity was 98/m*. In New York Bight, lowest density (0.1/m2) occurred at the midpoint, 16.0°-19.9°C, of the five classes in which bryozoans were found. Values increased disproportionately on either side of this class. Density values in Chesapeake Bight in- creased as temperature range broadened in the three classes in which they occurred. Densities were 8/m* in both the 12.0°-15.9°C class and the 16.0°-19.9°C class, and 11/m> in the 20.0°%-23.9°C class. The bio- mass of bryozoans in the three subareas was mod- erately small, and only in Southern New England did biomass values exceed 1 g/m' (ranging from 0.004 g/m" to 9 g/m*?). Biomasses in the New York Bight subarea ranged from 0.001 g/m" to 0.3 g/m. In the three classes in Chesapeake Bight in which bryozoans occurred, their biomasses ranged from 0.02 to 0.3 g/m. Brachiopoda were found in only one temperature class (16.0°%-19.9°C) in Chesapeake Bight and were absent in the other two subareas. Both density and biomass of brachiopods were low, 0.1/m' density weighing 0.001 g/m. Echinodermata as a group were significant con- tributors to the overall macrofauna of the Middle Atlantic Bight region and were found in all tem- perature ranges in each of the subareas. As a group, the density of echinoderms was highest in Southern New England and diminished to the south. However, ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES largest biomasses were found in New York Bight, second highest in Southern New England, and lowest in Chesapeake Bight. The detailed analysis of the subcomponents of the echinoderms follows. Holothuroidea were found in all temperature ranges in Southern New England, but not in the other two subareas. In New York Bight, they oc- curred in five of the seven temperature classes and were absent in the 4.0°-7.9°C and the 24.0°+C classes; in Chesapeake Bight, they occurred in six of the seven and were absent in the 8.0°%-11.9°C class. Density values were highest in Southern New England, intermediate in Chesapeake Bight, and lowest in New York Bight. In Southern New Eng- land, density ranged from 0.2/m* to 12/m*. In New York Bight, densities ranged from 0.06/m* to 2/m*. In Chesapeake Bight, densities ranged from 0.06/m* to 10/m*. The biomass of holothurians paralleled the distribution of density.values; largest biomasses oc- curred in Southern New England, second largest in Chesapeake Bight, and smallest in New York Bight. Biomasses ranging from 0.03 g/m* to 38 g/m" oc- curred in Southern New England. In New York Bight, only one class contained biomass greater than 1 g/m"; that was the 0°%-3.9°C class where 2 g/m occurred. The biomass in the remaining temperature classes increased from 0.1 g/m to 0.6 g/m* as the temperature range narrowed. Biomass of holo- thurians in Chesapeake Bight was highest (23 g/m") in the 12.0°%-15.9°C class, and lowest (0.05 g/m) in the 24.0° +C class. Echinoidea occurred in nearly all temperature- range classes in each of the subareas, and were ab- sent from only the 24.0°+C class in Southern New England, the 0°%-3.9°C class in New York Bight, and the 0°-3.9°C and 4.0°-7.9°C classes in Chesapeake Bight. Overall densities were highest in New York Bight, intermediate in Chesapeake Bight, and lowest in Southern New England. Highest density recorded in New York Bight was 108/m>* in the 20.0°%-23.9°C class. The next highest density (43/m>) in this class was in Chesapeake Bight, whereas density in South- ern New England for this class was only 7/m*. The next highest density of echinoids was 36/m* in the 16.0°-19.9°C class in New York Bight; in Chesa- peake Bight in the same class, 10/m> were found, whereas were recorded in Southern New Eng- land. The lowest overall value occurred in the 0° 3.9°C class in Southern New England where 0.2/m* was found. Biomasses of echinoids shifted somewhat, and, as in density values, greatest amounts occurred in New York Bight, but the second greatest amounts occurred in Southern New England, and smallest in MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION Chesapeake Bight. The largest biomass occurred in the 16.0°-19.9°C class in New York Bight, where 70 g/m' were found. Comparatively, 21 g/m and 16 g/m* occurred in the same class in Chesapeake Bight and Southern New England, respectively. The second largest biomass occurred in the 8.0°%-11.9°C class in Southern New England where 27 g/m* of organisms were found. In the same class in New York Bight, biomass was 7 g/m; but in Chesapeake Bight, it had diminished to 0.1 g/m*. Ophiuroidea were found in all temperature-range classes in both Southern New England and Chesa- peake Bight, but in New York Bight it was absent from the 16.0°-19.9°C and 24.0°+C classes. Highest densities by a substantial margin occurred in South- ern New England where 349/m* and 165/m' were found in the 8.0°%-11.9°C and 12.0°-15.9°C classes, respectively. In the comparable classes in Chesapeake Bight, the values were 3/m* and 90/m* and in New York Bight, and 0.4/m'. High density also occurred in the 4.0°-7.9°C class in Southern New England where 85/m' were recorded. The distribu- tion of brittle star biomass was similar to that of density, in that largest biomasses occurred in South- ern New England, second largest in New York Bight, and smallest amounts in Chesapeake Bight. Largest biomass, 25 g/m, was found in the 8.0°%-11.9°C class in Southern New England, and 17 g/m were found in the 4.0°%-7.9°C class in the same subarea. In similar classes in New York Bight, the values were 3 and 2 g/m, respectively; but in Chesapeake Bight, the values were 0.04 and 0.2 g/m. Asteroidea were present in all temperature ranges in Southern New England, which also contained the highest densities of sea stars. In New York Bight, as- teroids were present in five of the seven temperature- range classes and absent from the 16.0°-19.9°C and the 24.0° +C classes; in Chesapeake Bight, they were present in six classes and absent from the 4.0°-7.9°C class. Highest densities of sea stars, 3.9/m', in Southern New England were found in 16.0°-19.9°C, and in 8.0%-11.9°C and 12.0%-15.9°C; the remaining classes contained fewer than 1/m*. The second highest density of sea stars, was found in New York Bight in 8.0°%-11.9°C class, and 1.6/m> and 1/m in the 4.0°-7.9°C and 20.0°-23.9°C classes, respectively; fewer than 1/m' occurred in the other classes. Chesapeake Bight contained the lowest overall density of sea stars, and in no tem- perature class did the density exceed 0.5/m*. Sea star biomass was largest in the New York Bight subarea, followed by Southern New England and Chesapeake Bight. The largest biomass, 15 g/m, occurred in the 8.0°%-11.9°C class in New York Bight. N191 The next largest biomass, 7 g/m, occurred in South- ern New England in 12.0°-15.9°C. In Southern New England, only one other temperature range class, 8.0°-11.9°C, contained a moderately large biomass, 2.2 g/m. All other classes in this subarea had bio- masses of sea stars less than 1 g/m. In New York Bight, four classes contained biomass in excess of 1 g/m; these were 4.0°-7.9°C (1 g/m*), 8.0°-11.9°C (15 g/m) 12.0%-15.9°C (8 g/m), and 20.0°%-28.9°C (6 g/m>). 0.07 g/m occurred in the 0°-3.9°C class in this subarea. Chesapeake Bight biomasses were small. Largest in this subarea was 0.6 g/m in the 16.0°-19.9°C class and 0.04 g/m? in the 12.0°-15.9°C. In the remaining temperature classes, the biomass of sea stars ranged from trace amounts to 0.008 g/m. Hemichordata were sparsely distributed through- out the Middle Atlantic Bight region. They occurred in only three temperature classes in Southern New England, where densities ranged from O0.1/m' to 0.8/m*: and biomass ranged from 0.001 to 0.10 g/m'. In New York Bight subarea, hemichor- dates were found in only one temperature class, 20.0°-23.9°C, where 0.25/m* weighing 0.02 g/m* were found. In Chesapeake Bight, hemichordates were found in only the 20.0°%-23.9°C class where density was 0.2/m> and biomass, 0.08 g/m. Ascidiacea occurred in all temperature ranges in Southern New England and in all except the broadest range in New York Bight; they were present in five classes in Chesapeake Bight, and absent from the 4.0°-7.9°C and 8.0°-11.9°C classes. Greatest den- sities and biomass were found in Southern New England, next greatest in Chesapeake Bight, and lowest in New York Bight. Average densities in Southern New England ranged from 2/m' in 0°-3.9°C to 105/m* in 20.0°-23.9°C. On the whole, in this subarea, density increased as temperature range broadened to the 20.0°-23.9°C class and then dropped to 36/m* in the 24.0°+C class. In Chesa- peake Bight, density ranged from 0.65/m* to 21/m. In New York Bight, densities ranged from 0.1/m* to No definite relationship was discernible between density and temperature range in New York Bight. Ascidian biomass in Southern New England ranged from 0.1 g/m? in both the 0°-3.9°C and the 4.0°%-7.9°C classes to 23 g/m in both the 20.0°-23.9°C and the 24.0°+C classes. As tempera- ture range broadened in this subarea, an increase in biomass was apparent. In Chesapeake Bight, the same relationship was seen-lowest biomass, 0.07 g/m?, was recorded in the narrowest range class and highest, 15 g/m, in the broadest class. Ascidian biomass in New York Bight ranged from 0.02 g/m to 1 g/m. N192 DOMINANT FAUNAL COMPONENTS The purpose of this section is to identify and describe the taxonomic groups that constitute the principal faunal components at each sampling site station. Sites having the same dominant groups were combined to make patterns of distribution more dis- tinct, and these patterns facilitate our understanding of the faunal composition and its distribution. The term "dominance", as used in this report, refers to the taxonomic group that, mathematically, contrib- uted the highest number of individuals or greatest total accumulated wet weight. Again, it has been necessary to express the results in both density and biomass, because of the marked differences revealed by each. In numbers of individuals, six taxonomic groups were dominant: Bivalvia, Annelida, Echinoidea, Ophiuroidea, Crustacea, and the bathyal group. All except the bathyal group are composed of a single taxonomic component; the bathyal group is an as- semblage of several taxonomic groups, including such diverse forms as Pogonophora, Anthozoa, Sipunculida, Echiura, and Holothuroidea. In bio- mass, the dominant components were: Holothu- roidea, Bivalvia, Annelida, Echinoidea, Ophiuroidea, and the bathyal group. BAYS AND SOUNDS Dominant faunal components in the bays and sounds were characterized by their diversity. Many sites relatively close to one another, even adjacent stations, supported faunas of totally different domi- nant forms. In numbers of individuals, three faunal groups commonly constituted the principal faunal compo- ents in the bays and sounds: Crustacea, Annelida, and Bivalvia (fig. 123). In the Southern New Eng- land subarea, Crustacea was the group most widely distributed. In New York Bight and Chesapeake Bight, the dominant components were more equally divided among all three groups: Crustacea, Anne- lida, and Bivalvia. In biomass, only two taxonomic groups were im- portant as dominant components: Annelida and Bi- valvia (fig. 124). In all geographic areas, these two groups were more or less equally distributed in the bays and sounds. CONTINENTAL SHELF Six groups were important as dominant taxa on the Continental Shelf : Bivalvia, Annelida, Crustacea, Echinoidea, Ophiuroidea, and Holothuroidea. Each of these groups (except Ophiuroidea) differed markedly in geographic distribution and area oc- ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES cupied when their dominance in terms of density was compared to their dominance in biomass. There were few, but profound, differences in composition of dominant taxa evaluated according to density as compared with biomass. Taxonomic groups that were dominant in both density and biomass were: Bi- valvia, Annelida, Echinoidea, and Ophiuroidea. In number of individuals, dominant taxa (fig. 123) were Bivalvia, Annelida, Echinoidea, Ophiuroidea, and Crustacea. Crustacea was by far the most im- portant group in areal coverage. This group was particularly prominent in Southern New England and New York Bight. Even in Chesapeake Bight, Crustacea was the most widespread group, but was not overwhelmingly so as it was in the two northern subareas. Annelida was dominant in moderate-size areas throughout the Middle Atlantic Bight. Bivalvia and Echinoidea were dominant mainly in New York Bight and Chesapeake Bight. Ophiuroidea was the principal component only in the outer-shelf areas in Southern New England and northern New York Bight. In biomass (fig. 124), the distributional pattern of dominant taxons was strikingly different from that described above for the number of individuals. In the Southern New England subarea, Annelida and Bivalvia were the groups having the greatest geo- graphic coverage. Holothuroidea and Ophiuroidea were important in moderately small areas of the mid- and outer-shelf regions. In New York Bight, Bivalvia was the major group and Echinoidea was moderately important in the southern part. Ophiu- roidea dominated only in a small area along the Outer Continental Shelf in Southern New England and the northern part of New York Bight. In Chesapeake Bight, Echinoidea was the most widely distributed group, and Bivalvia and Annelida were the dominant forms in moderate-size areas. CONTINENTAL SLOPE Dominant taxa on the Continental Slope were limited primarily to Bivalvia, Annelida, and the bathyal group. In number of individuals, the faunas on the Con- tinental Slope in Southern New England and New York Bight were dominated about equally by Bi- valvia and Annelida (fig. 123). Farther south in Chesapeake Bight, the bathyal group was dominant in the deeper part of the slope. The bathyal group, Bivalvia, and Annelida constituted the major com- ponents in this subarea. In biomass, the dominant taxa were Annelida, par- ticularly along the upper slope, and the bathyal group, especially on the lower slope (fig. 124). MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION N193 DOMINANT TAXON Number of individuals Bivalvia Echinoidea S= Ophiuroidea Crustacea Bathyal group o FIGURE 123.-Geographic distribution of the number of individuals for each dominant taxon in the entire Middle Atlantic Bight region. N194 ATLANTIC CONTINENTAL SHELF AND SLOPE OF THE UNITED STATES DOMINANT TAXON Biomass Holothuroidea Bivalvia Anelia Echinoidea = Ophiuroidea Bathyal group FiqgUrE 124.-Geographic distribution of the biomass for each dominant taxon in the entire Middle Atlantic Bight region. MACROBENTHIC INVERTEBRATE FAUNA OF THE MIDDLE ATLANTIC BIGHT REGION CONTINENTAL RISE Dominant taxa on the Continental Rise were lim- ited to three major groups: Bivalvia, the bathyal group, and Annelida. In number of individuals, only two groups con- stituted the principal components: Bivalvia and the bathyal group. Bivalvia were dominant in a mod- erately large area in the shallower parts of the Con- tinental Rise (fig. 123), and the bathyal group was dominant in a large area including the deeper parts of the rise. In biomass, also, only two groups were dominant: Annelida and the bathyal group (fig. 124). Annelida contributed the principal biomass component in a relatively small and narrow geographic area in the shallower parts of the Continental Rise. The bathyal group, on the other hand, was dominant over a large geographic area, including all the deepwater parts of the rise. ACKNOWLEDGMENTS We thank the many persons who assisted with this study. Those who aided in organization and planning were: Herbert W. Graham, Robert LL. Edwards, and K. O. Emery. Personnel from the Northeast Fisheries Center who assisted with the biological work were: Bruce R. Burns, Philip H. Chase, Jr., Christopher P. Ciano, Evan B. Haynes, Henry W. Jensen, Barbara Langevin, Lewis M. Lawday, Arthur S. Merrill, Harriett E. Murray, Clifford D. Newell, Carol Schwamb, Ruth Stoddard Byron, Rodman E. Taylor, Jr., and Ellen J. Winchell. James O0. Farlow, Edward M. Handy, and John P. Laird provided assistance with computer program- ming. Frank A. Bailey and John R. Lamont assisted with drafting. Scientists from the U.S. Geological Survey and Woods Hole Oceanographic Institution marine geology group who provided sedimentological information or participated in shipboard work, of which biological sampling was an ancillary part, were: John C. Hathaway, Jobst Hiilsemann, Frank Manheim, Robert H. Meade, Richard M. Pratt, David Ross, John S. Schlee, James V. A. Trumbull, and Elazar Uchupi. Those who generously provided taxonomic assist- ance were: Edward L. Bousfield, Susan Brown- Leger, John C. McCain, Edward B. Cutler, Lion F. Gardner, Porter M. Kier, Peter Kinner, Louis S. Kornicker, John N. Kraeuter, Don Maurer, Arthur S. Merrill, Roy Olerdd, David L. Pawson, Frank Perron, Marian H. Pettibone, Thomas Phelan, Harold H. Plough, Johanna Reinhart, Howard L. Sanders, Thomas J. M. Schopf, Eve C. Southward, N195 J. H. Stock, Lowell P. Thomas, Ruth D. Turner, Bernt Widersten, Austin B. Williams, Lev A. Zenke- vitch, and Victor A. Zullo. Captain Arthur D. 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Atlantic Continental Shelf and Slope of the United States PROFESSIONAL PAPEN 35 29 This volume was published as separate chapters A-N UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, Secretary GEOLOGICAL SURVEY Doyle G. Frederick, Acting Director CONTENTS [Letters designate the chapters] (A) Atlantic Continental Shelf and Slope of the United States-Geologic Background, by K. O. Emery. (B) Atlantic Continental Shelf and Slope of the United States- Physiography and Sediments of the Deep-Sea Basin, by Richard M. Pratt. (C) Atlantic Continental Shelf and Slope of the United States- Physiography, by Elazar Uchupi. (D) Atlantic Continental Shelf and Slope of the United States- Color of Marine Sediments, by Daniel J. Stanley. (E) Atlantic Continental Shelf and Slope of the United States-Ostracode Zoogeography in the Southern Nova Scotian And Northern Virginian Faunal Provinces, by Joseph E. Hazel. (F) Atlantic Continental Shelf and Slope of the United States - Nineteenth Century Exploration, by Thomas J. M. Schopf. (G) Atlantic Continental Shelf and Slope of the United States-Heavy Minerals of the Continental Margin From Southern Nova Scotia to Northern New Jersey, by David A. Ross. (H) Atlantic Continental Shelf and Slope of the United States- Gravels of the Northeastern Part, by Richard M. Pratt. (I) Atlantic Continental Shelf and Slope of the United States- Shallow Structure, by Elazar Uchupi. (J) Atlantic Continental Shelf and Slope of the United States-Petrology of the Sand Fraction of Sediments, Northern New Jersey to Southern Florida, by John D. Milliman. (K) Atlantic Continental Shelf and Slope of the United States-Sand-Size Fraction of Bottom Sediments, New Jersey to Nova Scotia, by James V. A. Trumbull. (L) Atlantic Continental Shelf and Slope of the United States-Sediment Texture of the North- eastern Part, by John Schlee. (M) Atlantic Continental Shelf and Slope of the United States-Texture of Surface Sediments from New Jersey to Southern Florida, by Charles D. Hollister. (N) Atlantic Continental Shelf and Slope of the United States- Macrobenthic Invertebrate Fauna of the Middle Atlantic Bight Region-Faunal Composition and Quantitative Distribution, by Roland L. Wigley and Roger B. Theroux.