420 f 4& °^c 0( Jt&. ^TES 0< " /■ NOAA Technical Report NMFS Circular 420 Preliminary Keys to Otoliths of Some Adult Fishes of the Gulf of Alaska, Bering Sea, and Beaufort Sea James E. Morrow February 1979 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service NOAA TECHNICAL REPORTS National Marine Fisheries Service, Circulars The major responsibilities of the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and geographic distribution of fishery resources, to understand and predict fluctuations in the quantity and distribution of these resources, and to establish levels for optimum use of the resources. 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Technical papers originating in economics studies and from management in- vestigations appear in the Circular series. NOAA Technical Report NMFS Circulars are available free in limited numbers to governmental agencies, both Federal and State. They are also available in exchange for other scientific and technical publications in the marine sciences. Individual copies may be obtained (unless otherwise noted) from D825, Technical Information Division, Environmental Science Information Center, NOAA. Washington, D.C. 20235. Re- cent Circulars are: 365. Processing EASTROPAC STD data and the construction of ver- tical temperature and salinity sections by computer. By Forrest R. Miller and Kenneth A. Bliss. February 1972, iv + 17 p., 8 figs., 3 app. figs. For sale bv the Superintendent of Documents, U.S. Government Printing Of- fice. Washington, D.C. 20402. 366. Key to field identification of anadromous juvenile salmonids in the Pacific Northwest. By Robert J. MacConnell and George R. Snyder. January 1972, iv + 6 p., 4 figs. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 377. Fishery publications, calendar year 1970: Lists and indexes. By Mary Ellen Engett and Lee C. Thorson. December 1972, iv + 34 p., 1 fig. For sale bv the Superintendent of Documents, U.S. Government Printing Office. Washington, D.C. 20402. 378, Marine flora and fauna of the northeastern United States. Protozoa: Ciliophora. By Arthur C. Borror. September 1973, iii + 62 p., 5 figs. For sale bv the Superintendent of Documents, U.S. Government Printing Office. Washington, D.C. 20402. 367. Engineering economic model for fish protein concentration processes. Bv K. K. Almenas. L. C. Durilla, R. C. Ernst. J. W. Gentry. M. B. Hale, and J. M. Marchello. October 1972, iii + 175 p., 6 figs., 6 tables. For sale bv the Superintendent of Documents, U.S. Government Printing Office, Washington. D.C. 20402. 368. Cooperative Gulf of Mexico estuarine inventory and study, Florida: Phase I, area description. By J. Kneeland McNulty, William N. Lindall. Jr., and James E. Sykes. November 1972, vii + 126 p., 46 figs., 62 tables. For sale bv the Superintendent of Documents, U.S. Government Printing Office. Washington. D.C. 20402. 369. Field guide to the anglefishes (Pomacanthidae) in the western Atlantic. By Henry A Feddern. November 1972, iii + 10 p., 17 figs. For sale by the Superintendent of Documents, U.S. Government Printing Of- fice. Washington, D.C. 20402. 370. Collecting and processing data on fish eggs and larvae in the California Current region. By David Kramer, Mary J. Kalin, Elizabeth G. Stevens, James R. Thrailkill, and James R. Zweifel. November 1972, iv + 38 p., 38 figs., 2 tables. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 371. Ocean fishery management: Discussion and research. By Adam A. Sokoloski (editor). (17 papers, 24 authors.) April 1973, vi + 173 p., 38 figs., 32 tables. 7 app. tables. 379. Fishery publications, calendar year 1969: Lists and indexes. By Lee C. Thorson and Mary Ellen Engett. April 1973. iv + 31 p., 1 fig. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington, D.C. 20402. 3KO. Fishery publications, calendar year 1968: Lists and indexes. By Mary Ellen Engett and Lee C. Thorson. May 1973, iv + 24 p., 1 fig. For sale by the Superintendent of Documents, U.S. Government Printing Of- fice. Washington, D.C. 20402 381 . Fishery publications, calendar year 1967: Lists and indexes. By Lee C. Thorson and Mary Ellen Engett. July 1973, iv + 22 p., 1 fig. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 382. Fishery publications, calendar year 1966: Lists and indexes. By Mary Ellen Engett and Lee C. Thorson. July 1973, iv + 19 p.. 1 fig. For sale by the Superintendent of Documents, U.S. Government Printing Of- fice. Washington, D.C. 20402. 383. Fishery publications, calendar year 1965: Lists and indexes. By Lee C. Thorson and Mary Ellen Engett. July 1973, iv + 12 p., 1 fig. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington. D.C. 20402. 372. Fishery publications, calendar year 1971: Lists and indexes. By Thomas A. Manar. October 1972. iv + 24 p., 1 fcg. For sale by the Superintendent of Documents, U.F. Government Printing Office, Washington. D.C. 20402. 384. Marine flora and fauna of the northeastern United States. Higher plants of the marine fringe. By Edwin T. Moul. September 1973, iii + 60 p., 109 figs. For sale by the Superintendent of Documents, U.S. Govern- ment Printing Office, Washington, D.C. 20402. 374. Marine flora and fauna of the northeastern United States. Annelida: Oligochaeta. By David G. Cook and Ralph O. Brinkhurst. May 1973. iii + 23 p.. 82 figs. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 385. Fishery publications, calendar year 1972: Lists and indexes. By Lee C. Thorson and Mary Ellen Engett. November 1973, iv + 23 p., 1 fig. For sale bv the Superintendent of Documents, U.S. Government Printing Of- fice. Washington, D.C. 20402. 375. New Polychaeta from Beaufort, with a key to all species recorded from North Carolina. By John H. Day. July 1973, xiii + 140 p., 18 figs., 1 table. For -ale bv the Superintendent of Documents, U.S. Government Printing Office. Washington. D.C. 20402. 386. Marine flora and fauna of the northeastern United States. Pyc- nogonida. By Lawrence R. McCloskey. September 1973, iii + 12 p.. 1 fig. For sale bv the Superintendent of Documents, U.S. Government Printing Office. Washington, D.C. 20402. Tt Hottom-water temperatures on the continental shelf. Nova Scotia to New Jersey. By John B. Colton. Jr. and Ruth R. Stoddard. June 1973, iii + 55 p., 15 figs.. 12 app. tables. For sale by the Superintendent of Documents. U.S. Government Printing Office, Washington, D.C. 20402. 387. Marine flora and fauna of the northeastern United States. Crustacea: Stomatopoda. By Raymond B. Manning. February 1974, iii + 6 p.. 10 figs. For sale by the Superintendent of Documents, U.S. Govern- ment Printing Office, Washington. D.C. 20402. Continued on inside back cover ^MMOSP 1'fNT 0^ NOAA Technical Report NMFS Circular 420 Preliminary Keys to Otoliths of Some Adult Fishes of the Gulf of Alaska, Bering Sea, and Beaufort Sea James E. Morrow February 1979 % U o a Q =5 U.S. DEPARTMENT OF COMMERCE Juanita M. Kreps, Secretary National Oceanic and Atmospheric Administration Richard A. Frank, Administrator Terry L. Leitzell, Assistant Administrator tor Fisheries National Marine Fisheries Service The National Marine Fisheries Service (NMFS) does not approve, rec- ommend or endorse any proprietary product or proprietary material mentioned in this publication. No reference shall be made to NMFS, or to this publication furnished by NMFS, in any advertising or sales pro- motion which would indicate or imply that NMFS approves, recommends or endorses any proprietary product or proprietary material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this NMFS publication. CONTENTS Introduction 1 Accuracy 1 Potential problems and sources of error 2 Definitions 2 List of species included 2 Keys to families 5 Osmeridae 9 Gadidae 10 Zoarcidae 10 Trichodontidae 11 Bathymasteridae 11 Stichaeidae 11 Pholididae 12 Anarhichadidae 12 Scorpaenidae 12 Anoplopomatidae 14 Hexagrammidae 15 Cottidae 15 Agonidae 18 Cyclopteridae 19 Bothidae and Pleuronectidae (Pleuronectiformes) 19 Acknowledgments 21 Literature cited 21 Plates Plate I. Diagrams of medial sides of right otoliths, showing major features and measurements . . 22 Plate II. Otoliths of Antimoridae, Clupeidae, Cryptacanthodidae, Ammodytidae, Osmeridae, and Gadidae 23 Plate III. Otoliths of Gadidae, Zoarcidae, Trichodontidae, and Bathymasteridae 24 Plate IV. Otoliths of Stichaeidae, Pholididae, Anarhichadidae, and Scorpaenidae 25 Plate V. Otoliths of Scorpaenidae 26 Plate VI. Otoliths of Scorpaenidae, Anoplopomatidae, Hexagrammidae, and Cottidae 27 Plate VII. Otoliths of Cottidae 28 Plate VIII. Otoliths of Cottidae and Agonidae 29 Plate IX. Otoliths of Agonidae and Cyclopteridae 30 Plate X. Otoliths of Cyclopteridae, Bothidae, and Pleuronectidae 31 Plate XI. Otoliths of Pleuronectidae 32 in Digitized by the Internet Archive in 2013 http://archive.org/details/preliminarykeystOOmorr Preliminary Keys to Otoliths of Some Adult Fishes of the Gulf of Alaska, Bering Sea, and Beaufort Sea JAMES E. MORROW ABSTRACT Keys and outline drawings are provided for the identification of the otoliths of 142 species of marine fishes from the Gulf of Alaska, Bering Sea, and Beaufort Sea. INTRODUCTION Fish otoliths have proved useful in determining food habits of man, marine mammals, birds, fishes, crabs, and squids, to name a few. These otoliths may be found anywhere in the digestive tract of the predator (but es- pecially in the stomach), in droppings, or in kitchen mid- dens, camp sites, and garbage dumps of ancient man. The otoliths found in these situations have almost always suffered some degree of attrition from digestive action or breakage, or both, and this must be taken into considera- tion when making identifications. While the use of keys will, in the great majority of situations, lead to correct identifications, there is no sub- stitute for making direct comparisons, on a size-for-size basis, with known material. Those involved in food habits analyses and prey-predator studies should make a strong effort to build a comparative collection. For any given predator in a given area, this should not be dif- ficult. Normally, fewer than 10 species will account for more than 90% of the prey. The keys and illustrations presented here will put the food habits investigator at least in the right general group and show what species ought to be collected for purposes of comparison. It must be emphasized that neither stomach contents nor specimens from which otoliths are to be removed should ever be put into formaldehyde "for preservation until they can be worked on." Formaldehyde solution very quickly destroys the salient features needed for identification and renders otoliths so frangible that they crumble at a touch. Preparation of these keys was undertaken as a part of the Outer Continental Shelf Environmental Assessment Program of the Bureau of Land Management and the National Oceanographic and Atmospheric Administra- tion. The objective was to provide a means of identifying otoliths found in the stomachs of fishes, seabirds, and marine mammals, thus aiding analyses of food habits. The geographic area inhabited by the various species in- cluded ranges from the Gulf of Alaska northward through 'Division of Life Sciences, University of Alaska, Fairbanks, Alaska; present address: P.O. Box 605, Port Orford, OR 97465. the Bering and Chukchi Seas to the Beaufort Sea. The arrangement of groups and use of scientific and common names follow, with a few exceptions, Bailey et al. (1970) and Quast and Hall (1972). Geographic ranges are based on statements in the latter publication and include only the ranges in western North America. These keys are based on otoliths taken from fresh or frozen specimens of adult fishes. Because considerable changes in the shape and other features of the otolith may occur during development, the otoliths of post- larvae and young juveniles may not be susceptible of ac- curate identification from these keys. Freakish, ab- normal otoliths occur occasionally, even frequently in some groups, and these, likewise, cannot be reliably identified, although they can usually be keyed to family and sometimes generic level. There will also be a small percentage of normal, adult otoliths which will not key out properly. ACCURACY The otoliths of some species are highly variable. When- ever possible, these appear more than once in the keys to cover as much variation as possible. In some genera, the otoliths of various species are so similar that the reliability of species identification is low. Such genera or groups of species are combined in the keys, without attempting to carry the identification to species level. However, an otolith of each species is illustrated. These keys include 142 species of fishes known from Alaskan waters. Because of the nature of the collecting gear, shore fishes and pelagic species, in particular, are underrepresented. No attempt has been made to include scarce forms which are rarely encountered. Likewise, species which may be common elsewhere and occasional- ly venture into the area covered have not been included. It is therefore quite possible that species not included in the keys will be wrongly identified. However, the chances are good that correct identification can be made to the family level, perhaps even to genus. For those families where all Alaskan species are included, identification to the species level should be at least 75% accurate, perhaps even 90% accurate. Where 75% accuracy could not be achieved, species have been lumped together. Except for Stichaeus punctatus and Icelus canalicu- latus, each of which was represented in the study material by only a single pair of otoliths, we have had available from 4 to 20 pairs of otoliths of each species in- cluded in the keys. Accuracy of the keys was tested by keying out additional, known material, not only by us but also by five other biologists. In the light of the notes and remarks provided by these people, 75-90% accuracy seems about right. POTENTIAL PROBLEMS AND SOURCES OF ERROR It must be remembered that digestive acids and en- zymes tend to reduce the prominence of surface features of the otolith. Shape and features of the margin are gen- erally little affected until digestion has gone on for some time, but other features, such as the relative prom- inence of the cristae, may be affected quite soon. Al- lowance must be made for this when attempting to key out partially digested material. It may sometimes be necessary to resort to comparing such specimens with the illustrations. Comparison with known material is always desirable. Perhaps the most common error encountered in using the keys involves the decision as to whether or not an ex- cisura is present (Plate I). We found that, in some groups where excisurae (especially the minor) are normally pres- ent, the end of the sulcus is occasionally enclosed by a rim, leading to the conclusion that the excisura is absent (see section on Definitions). Where these anomalies were fairly frequent, the groups involved were included in more than one key. However, if an obviously erroneous identification is reached, it may be necessary to start again at the beginning and choose another alternative. Another problem encountered fairly frequently con- cerns the state of the cristae, whether well or poorly developed (see below). This can usually be solved by directing a beam of light nearly horizontally at the otolith, so that a well-developed crista casts a shadow as the otolith is turned this way and that. It may be neces- sary to pick the otolith up, using fine tweezers, and look along the length of the sulcus. This will almost always show the condition of the cristae. DEFINITIONS The following terms are used to designate certain features of the otolith (see also Plate I). This terminology is slightly modified from that used by Frizzell and Dante (1965). Antirostrum — The anterodorsal corner of the otolith, just dorsal to the notch of the excisura major. Cauda — The posterior portion of the sulcus, posterior to the collum. Colliculum — The raised portion of the floor of the sul- cus. May exist in the ostium, cauda, both, or neither. In some groups (e.g., the Scorpaenidae), the anterior colliculum may be so large as to obscure the notch of the excisura major. Collum — A constriction of the sulcus, usually (if pres- ent) located near the middle of the sulcus. Crista inferior — The ventral rim of the sulcus. If present as a distinct, raised ridge, it is termed "well devel- oped." If no ridge is present, the crista is "poorly devel- oped" or "absent." Crista superior — The dorsal rim of the sulcus. Same descriptive terms as for the crista inferior. Dorsal area — That portion of the otolith dorsal to the sulcus. Excisura — The opening of the sulcus on the margin of the otolith. The anterior opening of the sulcus is the excisura major, the posterior opening is the excisura minor. The excisurae often open into an excisural notch. If the sulcus does not reach the margin of the otolith, there is no excisura, even though a notch may be present. Height of dorsal area or ventral area — The greatest straight line distance from the center line of the sulcus to the dorsal or ventral margin of the otolith. Height of otolith — The greatest straight line distance from the dorsal to the ventral margin of the otolith, taken at right angles to the long axis. Height of rostrum — The distance, measured at right angles to the long axis, between the apex of the ex- cisural notch and the ventral margin of the otolith. If the notch is occluded by the colliculum, the height of the rostrum is measured to a horizontal through the point where the dorsal edge of the colliculum meets the margin of the otolith (Plate I). Length of otolith — The straight line distance from the most anterior to the most posterior margin of the otolith. Length of rostrum — The straight line distance from the tip of the rostrum to the apex of the excisural notch. If the notch is occluded by the colliculum, the length of the rostrum is measured to a vertical through the point where the dorsal edge of the colliculum meets the margin of the otolith (Plate I). Ostium. — The anterior portion of the sulcus, anterior to the collum. Postcaudal trough — A groove or depression on the posteroventral portion of the otolith, extending (when present) from the posterior end of the sulcus to the posteroventral margin of the otolith. Rostrum — The anterior extension of the ventral portion of the otolith below the excisural notch. Sulcus — The longitudinal groove on the medial surface of the otolith. Ventral area — That portion of the otolith ventral to the sulcus. LIST OF SPECIES INCLUDED Clupeidae Clupea harengus pallasi — Pacific herring. Chukchi Sea — California. Osmeridae Hypomesus olidus — Pond smelt. Arctic Alaska — California. Hypomesus pretiosus — Surf smelt. Bristol Bay — California. Mallotus uillosus — Capelin. Arctic Alaska — Wash- ington. Osmerus eperlanus — Rainbow smelt. Arctic Ocean — British Columbia. Spirinchus thaleichthys — Longfin smelt. Bristol Bay — San Francisco Bay. Thaleichthys pacificus — Eulachon. Bering Sea — California. Moridae Antimora microlepis — Longfin cod. Bering Sea — California. Gadidae Boreogadus saida — Arctic cod. Arctic Ocean, Chuk- chi Sea — Kuskokwim Bay. Eleginus gracilis — Saffron cod. Chukchi Sea — Gulf of Alaska. Gadus macrocephalus — Pacific cod. Bering Sea — California. Merluccius productus — Pacific hake. Gulf of Alaska — Gulf of California. Microgadus proximus — Pacific tomcod. Aleutian Islands — California. Theragra chalcogramma — Walleye pollock. Bering Sea — Baja California. Zoarcidae Bothrocara brunneum — Twoline eelpout. Bering Sea — California. Bothrocara molle — Soft eelpout. Bering Sea — Mexico. Bothrocara pusillum — Alaska eelpout. Bering Sea — Southeast Alaska. Embryx crotalina — Snakehead eelpout. Shumagin Islands — California. Lycodes brevipes — Shortfin eelpout. Bering Sea — Oregon. Lycodes diapterus — Black eelpout. Bering Sea — Cal- ifornia. Lycodes palearis — Wattled eelpout. Arctic Ocean — Washington. Lycodopsis pacifica — Blackbelly eelpout. Gulf of Alaska — California. Trichodontidae Arctoscopus japonicus — Sailfin sandfish. Bering Sea. Trichodon trichodon — Pacific sandfish. Bering Sea — California. Bathymasteridae Bathymaster caeruleofasciatus — Alaskan ronquil. Ber- ing Sea — Southeast Alaska. Bathymaster signatus — Searcher. Bering Sea — Washington. Ronquilus jordani — Northern ronquil. Bering Sea — California. Stichaeidae Acantholumpenus mackayi — Pighead prickle- back. Bering Sea, Aleutian Islands. Lumpenella longirostris — Longsnout prickle- back. Gulf of Alaska — British Columbia. Lumpenus fabricii — Slender eelblenny. Arctic Alaska — Southeast Alaska. Lumpenus maculatus — Daubed shanny. Arctic Alaska — Washington. Lumpenus sagitta — Snake prickleback. Bering Sea — California. Poroclinus rothrocki — Whitebarred prickle- back. Bering Sea — California. Stichaeus punctatus — Arctic shanny. Arctic Alaska — Southeast Alaska. Pholididae Apodichthys flavidus — Penpoint gunnel. Kodiak Is- land — California. Pholis ornata — Saddleback gunnel. Bering Sea — California. Anarhichadidae Anarhichas orientalis — Bering wolffish. Bering Sea. Anarrhichthys ocellatus — Wolf-eel. Gulf of Alaska — California. Cryptacanthodidae Delolepis gigantea — Giant wrymouth. Bering Sea — California. Lyconectes aleutensis — Dwarf wrymouth. Bering Sea — California. Ammodytidae Ammodytes hexapterus — Pacific sandlance. Arctic Alaska — California. Scorpaenidae Sebastes aleutianus — Rougheye rockfish. Aleutian Islands — California. Sebastes alutus — Pacific ocean perch. Bering Sea — California. Sebastes aurora — Aurora rockfish. Prince William Sound — California. Sebastes babcocki — Redbanded rockfish. Aleutian Islands — California. Sebastes borealis — Shortraker rockfish. Bering Sea — Oregon. Sebastes breuispinis — Silvergray rockfish. Bering Sea — California. Sebastes caurinus — Copper rockfish. Kenai Penin- sula — California. Sebastes ciliatus — Dusky rockfish. Bering Sea — Southeast Alaska. Sebastes crameri — Darkblotched rockfish. Bering Sea — California. Sebastes entomelas — Widow rockfish. Southeast Alaska — California. Sebastes maliger— Quillback rockfish. Gulf of Alaska — California. Sebastes melanops — Black rockfish. Aleutian Islands — California. Sebastes melanostomus — Blackgill rockfish. Bering Sea — Baja California. Sebastes mystinus — Blue rockfish. Bering Sea — Cal- ifornia. Sebastes polyspinis — Northern rockfish. Bering Sea — Southeast Alaska. Sebastes proriger — Redstripe rockfish. Bering Sea — California. Sebastes ruberrimus — Yelloweye rockfish. Gulf of Alaska — California. Sebastes uariegatus — Harlequin rockfish. Unimak Pass — Queen Charlotte Sound. Sebastes zacentrus — Sharpchin rockfish. Gulf of Alaska — California. Sebastolobus alascanus — Shortspine thorny- head. Bering Sea — Baja California. Sebastolobus altivelis — Longspine thornyhead. Aleu- tian Islands — Baja California. Anoplopomatidae Anoplopoma fimbria — Sablefish. Bering Sea — Cal- ifornia. Erilepis zonifer — Skilfish. Gulf of Alaska — Califor- nia. Hexagrammidae Hexagrammos decagrammus — Kelp green- ling. Aleutian Islands — California. Hexagrammos lagocephalus — Rock greenling. Ber- ing Sea — California. Hexagrammos octogrammus — Masked green- ling. Bering Sea — Southeast Alaska. Hexagrammos stelleri — Whitespotted green- ling. Bering Sea — California. Ophiodon elongatus — Lingcod. Kodiak Island — Baja California. Pleurogrammus monopterygius — Atka mack- erel. Bering Sea — California. Cottidae Artedius fenestralis — Padded sculpin. Aleutian Islands — California. Artedius harringtoni — Scalyhead sculpin. Gulf of Alaska — Southern California. Blepsias bilobus — Crested sculpin. Bering Sea — British Columbia. Belpsias cirrhosus — Silverspotted sculpin. Bering Sea — California. Dasycottus setiger — Spinyhead sculpin. Bering Sea — Washington . Enophrys bison — Buffalo sculpin. Gulf of Alaska — California. Enophrys diceraus — Antlered sculpin. Bering Sea — Southeast Alaska. Enophrys sp. — Bering Sea. Gymnocanthus galeatus — Armorhead sculpin. Ber- ing Sea — Southeast Alaska. Gymnocanthus tricuspis — Arctic staghorn scul- pin. Arctic Ocean — Bering Sea. Hemilepidotus hemilepidotus — Red Irish lord. Ber- ing Sea — California. Hemilepidotus jordani — Yellow Irish lord. Bering Sea — Southeast Alaska. Hemilepidotus spinosus — Brown Irish lord. South- east Alaska — California. Hemitripterus bolini — Bigmouth sculpin. Bering Sea — British Columbia. Icelinus borealis — Northern sculpin. Bering Sea — Washington. Icelus canaliculatus — No common name. Bering Sea. Icelus spatula — Spatulate sculpin. Bering Sea, Arc- tic Ocean. Icelus spiniger — No common name. Bering Sea — Southeast Alaska. Leptocottus armatus — Pacific staghorn scul- pin. Gulf of Alaska — Baja California. Malacocottus kincaidi — Blackfin sculpin. Bering Sea — Washington . Megalocottus platycephalus — Belligerent sculpin. Chukchi and Bering Seas. Myoxocephalus jaok — Plain sculpin. Chukchi Sea — Aleutian Islands. Myoxocephalus polyacanthocephalus — Great sculpin. Bering Sea — Washington. Myoxocephalus quadricornis — Fourhorn scul- pin. Arctic Ocean — Bering Sea. Myoxocephalus scorpius — Shorthorn sculpin. Chuk- chi Sea — Aleutian Islands. Nautichthys robustus — No common name. Aleutian Islands — British Columbia. Psychrolutes paradoxus — Tadpole sculpin. Bering Sea — Washington . Radulinus asprellus — Slim sculpin. Gulf of Alaska — Baja California. Rhamphocottus richardsoni— Grunt sculpin. Bering Sea — California. Triglops forficata — Scissortail sculpin. Bering Sea — Gulf of Alaska. Triglops macellus — Roughspine sculpin. Bering Sea — Washington. Triglops pingeli — Ribbed sculpin. Chukchi Sea — Washington. Triglops scepticus — Spectacled sculpin. Bering Sea — Gulf of Alaska. Agonidae Agonus acipenserinus — Sturgeon poacher. Point Barrow — Washington. Anoplagonus inermis — Smooth alligatorfish. Aleu- tian Islands — British Columbia. Bathyagonus alascanus — Gray starsnout. Bering Sea — Washington . Bathyagonus infraspinatus — Spinycheek star- snout. Bering Sea — California. Bathyagonus nigripinnis — Blackfin poacher. Bering Sea — Oregon. Bathyagonus pentacanthus — Bigeye poacher. Ber- ing Sea — California. Hypsagonus quadricornis — Fourhorn poacher. Ber- ing Sea — Washington. Occella dodecaedron — Bering poacher. Bering Sea — northern Gulf of Alaska. Occella verrucosa — Warty poacher. Bristol Bay — California. Pallasina barbata — Tubenose poacher. Bering Sea — Puget Sound. Sarritor frenatus — Sawback poacher. Bering Sea — Southeast Alaska. Sarritor leptorhynchus — Longnose poacher. Bering Sea — Gulf of Alaska. Cyclopteridae Careproctus furcellus — No common name. Bering Sea. Careproctus melanurus — Blacktail snailfish. Aleu- tian Islands — California. Careproctus sp. — Bering Sea. Eumicrotremus orbis — Pacific spiny lumpsucker. Chukchi Sea — Washington. Liparis dennyi — Marbled snailfish. Gulf of Alaska — Washington. Liparis gib bus — No common name. Chukchi Sea — Southeast Alaska. Liparis liparis — Striped seasnail. Arctic Ocean, Chukchi Sea. Liparis pulchellus — Showy snailfish. Bering Sea — California. Nectoliparis pelagicus — Tadpole snailfish. Bering Sea — California. Bothidae Citharichthys sordidus — Pacific sanddab. Bering Sea — California. Pleuronectidae Atheresthes stomias — Arrowtooth flounder. Chuk- chi Sea — California. Eopsetta jordani — Petrale sole. Gulf of Alaska — Baja California. Glyptocephalus zachirus — Rex sole. Bering Sea — California. Hippoglossoides elassodon — Flathead sole. Chukchi Sea — Oregon. Hippoglossoides robustus — Bering flounder. Chuk- chi Sea — Aleutian Islands. Hippoglossus stenolepis — Pacific halibut. Bering Sea — California. Isopsetta isolepis — Butter sole. Bering Sea — Cal- ifornia. Lepidopsetta bilineata — Rock sole. Bering Sea — Cal- ifornia. Limanda aspera — Yellowfin sole. Chukchi Sea — British Columbia. Limanda proboscidea — Longhead dab. Chukchi Sea — Bristol Bay. Liopsetta glacialis — Arctic flounder. Arctic Ocean — Bering Strait. Microstomus pacificus — Dover sole. Chukchi Sea — Baja California. Parophrys vetulus — English sole. Aleutian Islands — Baja California. Platichthys stellatus — Starry flounder. Bering Strait — California. Pleuronectes quadrituberculatus — Alaska plaice. Chukchi Sea — Washington. Psettichthys melanostictus — Sand sole. Gulf of Alaska — California. Reinhardtius hippoglossoides — Greenland hali- but. Chukchi Sea — California. KEYS TO FAMILIES A. Both excisurae present Key I B. Both excisurae absent Key II C. Excisura major present, excisura minor absent Key III Key I. Both Excisurae Present la. Sulcus divided into dorsal and ventral chambers by a long, thin, bladelike colliculum Antimora microlepis (Fig. 1) lb. Sulcus not divided as in la 2 2a. Height of otolith 55% or less of its length 3 2b. Height of otolith more than 55% of its length 5 3a. Notch of excisura major deep and narrow, forming an angle of much less than 90°. Dorsal and ventral margins of otolith roughly parallel. Ventral margin incised Clupea harengus pallasi (Fig. 2) 3b. Notch of excisura major broad, usually about 90° or more, always greater than 60°. Margins var- ious 4 5 4a. Ends of sulcus extremely deep. Collum well developed. A prominent notch in ventral margin below collum (except in juveniles). Tiny otoliths, never more than 2 mm long Family Pholididae . . Apodichthys flavidus (Fig. 39) 4b. Without the above combination of characters Family Salmonidae (some Oncorhynchus) 2 5a. Sulcus deep and well defined 6 5b. Sulcus shallow, rather poorly defined Family Trichodontidae, p. 11 6a. Greatest height of ventral area distinctly behind middle of otolith length Family Osmeridae, p. 9 6b. Greatest height of otolith about at middle of otolith length 7 7a. Angle of notch of excisura major less than 90°. A deep channel present below crista inferior .... Family Anarhichadidae . . . Anarrhichthys ocellatus (Fig. 41) 7b. Angle of notch of excisura major about 90° or more. No deep channel below crista inferior 8 8a. General shape more or less an equilateral triangle. Height of otolith 90% or more of its length, or thickness of otolith more than 50% of its length. A fan-shaped area dorsal to sulcus Family Zoarcidae (Genus Bothrocara), p. 10 8b. Not as in 8a Family Salmonidae (some Oncorhynchus)' 1 Key II. Both Excisurae Absent la. Sulcus well defined, consists either of a fairly deep, straight groove or of one or two pits 4 lb. Sulcus shallow and poorly defined 2 2a. Sulcus constricted at collum, broad at each end. Anterior end of otolith highest, otolith ta- pers posteriorly Family Gadidae, p. 10 2b. Sulcus not constricted at collum, about the same width throughout its length. Otolith not shaped as in 2a 3 3a. Sulcus straight. Surface of otolith like frosted glass. Otolith nearly round in cross section. Oto- lith of small to moderate size Family Cryptacanthodidae . . . Lyconectes aleutensis (Fig. 3) 3b. Sulcus arched dorsad. Surface of otolith not like frosted glass. Otolith compressed laterally, oval in cross section. Otolith tiny, never longer than 2 mm Family Cottidae . . . Psychrolutes paradoxus (Fig. 73) 4a. Otolith almond-shaped. Sulcus reaches or nearly reaches anterior tip 5 4b. Not as in 4a 6 2 For a key to otoliths of Oncorhynchus, see: Casteel, R. W. 1974. Identification of the species of Pacific salmon (Genus Oncorhynchus) native to North America based upon otoliths. Copeia 1974:305-311. 5a. Dorsal margin smooth. Height of otolith about 50% of its length. Sulcus fails to reach posterior end of otolith by more than 20% of otolith length. No crista superior. Otolith never longer than 3 mm Ammodytes hexapterus (Fig. 6) 5b. Dorsal margin crenulate or wavy. Height of otolith about 36% of its length. Sulcus fails to reach posterior margin of otolith by less than 10% of otolith length. Crista superior high, sharp. Otolith larger than in 5a Family Anoplopomatidae . . . some Anoptopoma fimbria (Fig. 65) 6a. Otolith thick, heavy, massive. Always a deep notch anteriorly, often a posterior notch also. A thick, rounded ridge separates ostium of sulcus from cauda Family Cryptacanthodidae . . . Delolepis gigantea (Figs. 4, 5) 6b. Not as in 6a 7 7a. Dorsal area with a deep, fan-shaped depression Family Zoarcidae . . . Embryx crotalina (Fig. 19) 7b. Not as in 7a 8 8a. Lateral side of otolith distinctly concave Family Cottidae, p. 15 8b. Lateral side of otolith flat to convex, not distinctly concave Pleuronectiformes, p. 19 Key III. Excisura Major Present, Excisura Minor Absent la. Long axis straight or nearly so when viewed from above 2 lb. Long axis distinctly curved 14 2a. Otolith almond-shaped. Sulcus opens at extreme tip Ammodytes hexapterus (Fig. 6) 2b. Otolith not almond-shaped. Sulcus opens somewhere behind extreme anterior tip 3 3a. Ends of sulcus extremely deep. Collum well developed. Tiny otoliths, never longer than 2 mm . Family Pholididae . . . Apodirhthys flavidus (Fig. 39) 3b. Not as in 3a 4 4a. Dorsal area of medial side with definite radiating lines 5 4b. Dorsal area without radiating lines 7 5a. Excisural notch shallow or absent. Rostrum not or scarcely longer than antirostrum 6 5b. Excisural notch generally obvious. Rostrum much longer than antirostrum Family Cyclopteridae, p. 19 6a. Height of otolith more than 65% of its length, usually more than 70% of length .... Family Trichodontidae, p. 11 6b. Height of otolith less than 65% of its length, usually less than 60% of length Family Cyclopteridae, p. 19 7 'a. Medial side flat, surfaces of dorsal and ventral areas in same plane. Rostrum not sharply sepa- rated from antirostrum Family Cyclopteridae, p. 19 ~b. Medial side more or less rounded, or surfaces of dorsal and ventral areas not in same plane, or rostrum prominent and clearly separated from antirostrum 8 Sa. Ventral margin of otolith distinctly curved 9 8b. Ventral margin straight or nearly so, at least in its middle portion 12 9a. Sulcus not parallel with long axis of otolith, may be curved 11 9b. Sulcus parallel with long axis of otolith 10 10a. Rostrum sharply pointed. Ventral margin deeply rounded. Dorsal margin irregular, but more or less parallel to sulcus Family Osmeridae, p. 9 10b. Not with the above combination of characters Family Cottidae, p. 15 11a. Excisural notch distinct, V-shaped. Rostrum pointed Family Stichaeidae . . . Poroclinus rothrocki (Fig. 34) lib. Excisural notch various. Rostrum rounded or blunt Family Agonidae (Genus Sarritor), p. 18 12a. Crista inferior forming at least a slight ridge Family Stichaeidae, p. 11 12b. Crista inferior poorly developed, not forming a ridge 13 13a. Rostrum short, blunt Family Agonidae, p. 18 13b. Rostrum long, pointed Family Anarhichadidae, p. 12 14a. Otolith heavy, massive. A thick, rounded ridge projects anteriorly in the sulcus and sepa- rates ostium from cauda horizontally Family Cryptacanthodidae . . . Delolepis gigantea (Figs. 4, 5) 14b. Not as in 14a 15 15a. Surface of otolith like frosted glass. Sulcus shallow, with a well-developed colliculum Family Cryptacanthodidae . . . Lyconectes aleutensis (Fig. 3) 15b. Surface not like frosted glass, or sulcus deep and without a colliculum 16 16a. Crista superior well developed, appears as a distinct ridge 19 16b. Crista superior poorly developed, not raised as a ridge above surface of dorsal area 17 17a. Ostium V-shaped, its bottom (lateral surface) flat, without a colliculum Family Pholididae . . . Pholis ornata (Fig. 40) 17b. Ostium various, but not with above combination of characters 18 8 18a. Excisural notch prominent and without a colliculum. Dorsal margin of otolith not deeply crenulate Family Agonidae, p. 18 18b. Excisural notch not prominent, or if prominent, there is a well -developed colliculum in the notch or the dorsal margin of the otolith is markedly crenulate Family Cottidae, p. 15 19a. Central axis of sulcus with a distinct ventrad bend at its posterior end 21 19b. Central axis of sulcus without a ventrad bend at its posterior end 20 20a. Height of otolith less than 45% of its length. Rostrum long and narrow, well separated ante- riorly from antirostrum Family Bathymasteridae . . . Bathy master signatus (Fig. 30) 20b. Height of otolith more than 45% of its length. If less, then rostrum short and broad and poorly separated from antirostrum Family Scorpaenidae, p. 12 21a. Postcaudal trough broad, well developed, meets posterior end of sulcus Family Hexagrammidae, p. 15 21b. Postcaudal trough absent (one or two grooves with V-shaped cross sections may be present), or, if present and broad, meets posteroventral end of sulcus 22 22a. Medial surface of otolith curved dorsoventrally Family Bathymasteridae, p. 11 22b. Medial surface of otolith nearly flat dorsoventrally Family Anoplopomatidae, p. 14 FAMILY OSMERIDAE la. Anteroventral margin rounded 3 lb. Anteroventral margin straight 2 2a. Posterodorsal and dorsal margins curved. Otolith height greatest at about two-thirds of length . Mallotus villosus (Fig. 7) 2b. Posterodorsal and dorsal margins straight or nearly so. Otolith height greatest at posterior end Thaleichthys pacificus (Fig. 8) 3a. Rostrum broad, its tip blunt. Dorsal rim of sulcus curves ventrad at posterior end. Post- caudal trough indistinct or absent Hypomesus pretiosus (Fig. 9) 3b. Rostrum narrow, more or less pointed. Dorsal rim of sulcus straight. Postcaudal trough distinct 4 4a. Posterior margin more or less truncate, approximately at right angles to long axis of sulcus .... v . Osmerus eperlanus (Fig. 10) 4b. Posterior margin rounded 5 5a. Height of otolith 59% (56-61%) of its length Spirinchus thaleichthys (Fig. 11) 5b. Height of otolith 67% (65-68%) of its length Hypomesus olidus (Fig. 12) FAMILY GADIDAE la. Medial surface strongly convex, lateral surface distinctly concave 2 lb. Medial surface only moderately convex, lateral surface flat or nearly so, or concave only above midline 3 2a. Height of otolith more than 44% of its length. Posterodorsal (more pointed end) margin forms angle of about 60° with longitudinal axis Gadus macrocephalus (Fig. 13) 2b. Height of otolith 44% or less of its length. Posterodorsal margin forms angle of about 45° with longitudinal axis .... Theragra chalcogramma (Fig. 14) 3a. Lateral surface smooth, without rounded lumps 4 3b. Lateral surface with rounded lumps, especially near center of otolith 5 4a. Anterodorsal (higher end) margin forms angle of 30°-45° (usually about 30°) with long axis. Anterior end rounded or with numerous, small lobules. Otoliths of adults may exceed 20 mm in length Merluccius productus (Fig. 15) 4b. Anterodorsal margin forms angle of 15°-25° (usually 20° or less) with long axis. Anterior end bilobed, a distinct notch separating the two lobes. Otoliths small, rarely over 8 mm long . . . Boreogadus saida (Fig. 16) 5a. Posterodorsal margin slightly concave, forms angle of 25°-30° (usually about 30°) with long axis. Posterodorsal rim quite thin Microgadus proximus (Fig. 17) 5b. Posterodorsal margin straight to slightly convex, forms angle of about 20° with long axis. Pos- terodorsal rim slightly thickened Eleginus gracilis (Fig. 18) FAMILY ZOARCIDAE la. Sulcus ends on rostrum, usually does not open on anterior margin. A deep groove, usually in the form of two elongate pits, below sulcus. A deep pit in dorsal area Embryx crotalina (Fig. 19) lb. Not as in la 2 2a. General shape approximately an equilateral triangle. Height of otolith 90% or more of its length, or thickness more than 50% of length (Genus Bothrocara) 3 2b. General shape more or less triangular, but not equilateral. Height of otolith less than 85% of length, thickness less than 50% of length 5 3a. Lateral side an exaggerated, round dome. Thickness more than 50% of length. Large speci- mens with ventral area expanded anteroposteriorly Bothrocara brunneum (Fig. 20) 3b. Lateral side convex, but not domelike. Thickness less than 50% of length. Ventral area not expanded both anteriorly and posteriorly 4 4a. Anteroventral corner expanded to form a short, rounded lobe Bothrocara pusillum (Fig. 21) 4b. Anteroventral comer not expanded Bothrocara molle (Fig. 22) 10 5a. Height of otolith 66% or less of its length Lycodopsis pacifica (Fig. 23) 5b. Height of otolith 69-83% of its length (Genus Lycodes) 6 6a. Dorsal margin more or less rounded. Greatest height of otolith at or behind middle of length. Posterodorsal margin typically convex Lycodes palearis (Fig. 24) 6b. Dorsal margin usually with a distinct angle. Greatest height of otolith at or before middle of length. Posterodorsal margin straight or concave 7 7a. Greatest height distinctly anterior to middle of length. Texture smooth Lycodes breuipes (Fig. 25) 7b. Greatest height near center of length. Texture less smooth Lycodes diapterus (Fig. 26) FAMILY TRICHODONTIDAE la. Rostrum short, blunt. Inner face of otolith thickened below center of sulcus Trichodon trichodon (Fig. 27) lb. Rostrum long, pointed. Inner face of otolith flat, not thickened Arctoscopus japonicus (Fig. 28) FAMILY BATHYMASTERIDAE la. Posterior end of otolith pointed Ronquilus jordani (Fig. 29) lb. Posterior end of otolith rounded or lobate 2 2a. Dorsal margin crenulate. Posterior end of sulcus bent ventrad at angle of 10°-15°. Height of oto- lith 40% or more of its length. Lateral surface with distinct radiating lines Bathy master signatus (Fig. 30) 2b. Dorsal margins wavy, not crenulate. Posterior end of sulcus bent ventrad at an angle of 20°. Height of otolith less than 40% of its length. Lateral surface smooth; if radiating lines are pres- ent, they are few in number and hard to see Bathymaster caeruleofasciatus (Fig. 31) FAMILY STICHAEIDAE la. Height of otolith 65% or more of its length 2 lb. Height of otolith less than 65% of its length, usually less than 60% 3 2a. Excisural notch very shallow Lumpenella longirostris (Fig. 32) 2b. Excisural notch deep and obvious Lumpenus maculatus (Fig. 33) 3a. Excisural notch deep and obvious. Anterior end of sulcus opens in notch 4 3b. Excisural notch poorly defined and/or sulcus does not open in the notch. A groove may be pres- ent from the notch to the dorsal edge of the sulcus 5 4a. Tip of rostrum pointed (rarely blunt), antirostrum angular Poroclinus rothrocki (Fig. 34) 4b. Both rostrum and antirostrum broadly rounded Acantholumpenus mackayi (Fig. 35) 11 5a. Excisural notch present, forming an angle of more than 45°. Height of dorsal area 1.0-1.2 times that of ventral area Lumpenus fabricii (Fig. 36) 5b. Excisural notch virtually absent, if present forms an angle of about 45°. Height of dorsal area 1.5-2.0 times that of ventral area 6 6a. A prominent lobe on posterodorsal margin Lumpenus sagitta (Fig. 37) 6b. No prominent lobe on posterodorsal margin Stichaeus punctatus (Fig. 38) FAMILY PHOLIDIDAE la. Sulcus very deep, reaches or almost reaches posterior margin. Crista inferior deeply under- cut. Often a notch near middle of ventral margin Apodichthys flavidus (Fig. 39) lb. Sulcus moderately deep, does not reach posterior margin. Crista inferior not undercut. No notch in ventral margin Pholis ornata (Fig. 40) FAMILY ANARHICHADIDAE la. Excisura major deep and narrow. A deep furrow present below crista inferior. Lateral sur- face usually with a clump of nodules in nuclear area Anarrhichthys ocellatus (Fig. 41) lb. Excisura major a rather shallow, V-shaped notch. Crista inferior scarcely evident, no fur- row below it. Lateral surface smooth Anarhichas orientalis (Fig. 42) FAMILY SCORPAENIDAE This key to the otoliths of Alaskan Scorpaenidae is based on adult specimens. The otoliths of juveniles (i.e., otoliths less than about 10 mm long) are all very similar, generally resembling the otoliths of the dwarf species Sebastes variegatus. They cannot be distinguished with any degree of reliability. la. Height of dorsal area about 2 x height of ventral area (only about 1 .2 x in small juveniles) Sebastolobus altivelis (Fig. 43) and S. alascanus (Fig. 44) lb. Height of dorsal and ventral areas about equal 2 2a. Height of otolith usually less than 45% of its length, always less than 50% 3 2b. Height of otolith more than 45% of its length 7 3a. Height of otolith 38-43% of its length. Dorsal margin nearly straight, although incised Sebastes entomelas (Fig. 45) 3b. Height of otolith 43-48% of its length. Dorsal margin slightly but distinctly convex 4 4a. Dorsal margin with coarse, broad irregularities 5 4b. Dorsal margin with small, fine incisions and irregularities 6 5a. Anterior portion of dorsal margin behind colliculum rounded. Postcaudal trough absent; if pres- ent, shallow and ends in a broad, shallow indentation of posteroventral margin . . . Sebastes brevispinis (Fig. 46) 5b. Anterior portion of dorsal margin behind colliculum nearly straight. Postcaudal trough promi- nent, ends in a deep notch in posteroventral margin Sebastes proriger (Fig. 47) 12 6a. Tip of rostrum pointed. Postcaudal trough prominent Sebastes caurinus (Fig. 48) 6b. Tip of rostrum blunt. Postcaudal trough poorly developed Sebastes mystinus (Fig. 49) 7a. Dorsal margin with fine, irregular incisions 8 7b. Dorsal margin not as in 7a, except on posterior portion in some species. If deeply incised, the incisions are coarse, the projections usually toothlike 10 8a. Height of ventral area 80% or more of height of dorsal area Sebastes maliger (Fig. 50) 8b. Height of ventral area less than 80% of height of dorsal area 9 9a. Posteroventral margin usually with one or two deep indentations Sebastes caurinus (Fig. 48) 9b. Posteroventral margin without deep indentations Sebstes melanostomus (Fig. 51) 10a. Ventral margin smooth (sometimes a few weak irregularities in Sebastes melanops) 11 10b. Ventral margin with crenulations, teeth or noticeable irregularities, at least on rostrum 14 11a. Height of otolith 60-68% of its length. Thickness of otolith about 30% of its height Sebastes aurora (Fig. 52) lib. Height of otolith less than 55% of its length. Thickness much less than 30% of height 12 12a. Height of otolith 50-54% of its length Sebastes ciliatus (Fig. 53) 12b. Height of otolith less than 50% (usually 45-49%) of its length 13 13a. Postcaudal trough follows axis of sulcus to posterior margin of otolith (a ventrally directed branch of the trough may be present) Sebastes melanops (Fig. 54) 13b. Postcaudal trough forms an angle of about 30° with axis of sulcus Sebastes polyspinis (Fig. 55) 14a. Crista inferior raised above surface of ventral area s^iST. 15 14b. Crista inferior not sharply set off from surface of ventral area (a longitudinal groove may be present in ventral area) / 22 15a. Height of otolith 46% or less of its length Sebastes breuispinis (Fig. 46) 15b. Height of otolith 49% or more of its length 16 16a. A prominent postcaudal trough present 17 16b. Postcaudal trough absent, or at least not prominent 20 17a. Postcaudal trough does not end in a notch on posteroventral margin Sebastes babcocki (Fig. 56) 17b. Postcaudal trough ends in an indentation in posteroventral margin 18 13 lSa. Dorsal margin smoothly rounded, except at posterior end Sebastes aurora (Fig. 52) 18b. Dorsal margin irregular and/or incised 19 19a. Ventral margin smooth or nearly so Sebastes zacentrus (Fig. 57) 19b. Ventral margin with numerous, small teeth , Sebastes maliger (Fig. 50) 20a. Posterior margin rounded, usually deeply incised, often almost frilly or fishtaillike 21 20b. Posterior margin truncate, not frilly or fishtaillike, sometimes with small, irregular projec- tions Sebastes borealis (Fig. 58) 21a. Usually one or two large indentations in posterodorsal margin Sebastes brevispinis (Fig. 46) 21b. No large indentations in posterodorsal margin Sebastes crameri (Fig. 59) 22a. Dorsal margin quite smooth (may have a few shallow crenulations) Sebastes variegatus (Fig. 60) and juvenile S. aleutianus 22b . Dorsal margin crenulate or irregularly incised 23 23a. Excisural notch fairly obvious, rostrum clearly set off from antirostrum 24 23b. Excisural notch shallow or absent, rostrum not clearly separated from antirostrum 25 24a. Posterior part of ventral margin of rostrum usually toothed or crenulate. Dorsal area usually with fine, radiating lines Sebastes alutus (Fig. 61) 24b. Posterior part of ventral margin of rostrum not toothed, but may have shallow crenulations or irregularities. Dorsal area without radiating lines Sebastes aleutianus (Fig. 62) 25a. Posterior margin of otolith crenulate to moderately incised Sebastes polyspinis (Fig. 55) 25b. Posterior margin of otolith deeply incised, frilly, onten fishtaillike 26 26a. Ventral margin more or less crenulate or toothed. Dorsal margin usually rather deeply incised, often frilly. Height of otolith 43-48% of its length (usually more than 45%) Sebastes caurinus (Fig. 48) 26b. Ventral margin smooth or slightly irregular. Dorsal margin with shallow incisions or crenula- tions, these usually deeper towards posterior end of otolith. Height of otolith 48% or more of its length Sebastes ruberrimus (Fig. 63) FAMILY ANOPLOPOMATIDAE la. Height of otolith 50-60% of its length. Crista superior overhangs sulcus, especially in large specimens Erilepis zonifer (Fig. 64) lb. Height of otolith 40-45% of length. Crista superior does not overhang sulcus Anoplopoma fimbria (Fig. 65) 14 FAMILY HEXAGRAMMIDAE la. Crista superior a well-defined ridge; crista inferior rises smoothly from surface of ventral area 2 lb. Both cristae prominent and well defined. Crista superior a sharp ridge; crista inferior rounded and heavy (Genus Hexagrammos) 3 2a. Rostrum pointed. Otolith small, rarely longer than 6 mm Pleurogrammus monopterygius (Fig. 66) 2b. Rostrum blunt. Otolith may exceed 12 mm long Ophiodon elongatus (Fig. 67) 3a. Tip of rostrum rounded 4 3b. Tip of rostrum pointed 5 4a. Crista inferior extremely prominent, undercut on ventral side. Collum prominent Hexagrammos lagocephalus (Fig. 68) 4b. Crista inferior a broad, thick ridge rising smoothly from surface of ventral area. Collum not especially prominent Hexagrammos stelleri (Fig. 69) 5a. Lateral surface without concentric rings Hexagrammos octogrammus (Fig. 70) 5b. Lateral surface with numerous concentric rings Hexagrammos decagrammus (Fig. 71) FAMILY COTTIDAE la. Both excisurae absent 2 lb. Excisura major present, excisura minor present or absent 7 2a. Long axis curved, lateral side concave 4 2b. Long axis straight 3 3a. Dorsal margin crenulate. Otoliths large, often exceed 8 mm long Dasycottus setiger (Fig. 72) 3b. Dorsal margin smooth. Otoliths tiny, never longer than 2 mm Psychrolutes paradoxus (Fig. 73) 4a. Ventral margin smooth or irregularly wavy 5 4b. Ventral margin more or less crenulate Genus Myoxocephalus (Figs. 75, 76, 77) 5a. Ventral margin curved. Height of otolith about 60% of its length Myoxocephalus quadricornis (Fig. 74) 5b. Ventral margin irregular, but nearly straight. Height of otolith about 50% of its length 6 6a. Dorsal margin with a few broad crenulations Enophrys bison (Fig. 97) 6b. Dorsal margin with more numerous, deeper crenulations Enophrys diceraus (Fig. 96) 15 Ta. Both excisurae present. Dorsal margin deeply crenulate, ventral margin smooth Malacocottus kincaidi (Fig. 78) rb. Excisura major present, excisura minor absent. Margins various 8a. Long axis straight or nearly so 9 8b. Long axis distinctly curved, usually strongly so 19 9a. One or more prominent bulges on lateral side, or ventral area notably thicker than dorsal area 10 9b. No prominent bulges on lateral side 13 10a. A moderate bulge on ventral area of lateral side with a central bulge dorsal to it and clearly outlined by grooves Nautichthys robustus (Fig. 79) 10b. A single, extremely prominent bulge on lateral side of ventral area, or ventral area notably thicker than dorsal area 11 11a. Dorsal margin with numerous, deep crenulations Malacocottus kincaidi (Fig. 78) lib. Dorsal margin with few, shallow crenulations or irregularities 12 12a. Rostrum short, blunt Blepsias bilobus (Fig. 80) 12b. Rostrum long, pointed Blepsias cirrhosus (Fig. 81) 13a. Height of otolith about 80% of its length Hemitripterus bolini (Fig. 82) 13b. Height of otolith much less than 80% of its length, usually less than 65% 14 14a. Dorsal margin crenulate (some Radulinus almost in 14b) 15 14b. Dorsal margin smooth or irregular 18 15a. Sulcus reaches anterior margin at or near tip of rostrum 17 15b. Sulcus ends anteriorly in excisural notch, does not reach tip of rostrum 16 16a. Sulcus bends dorsad anteriorly. Colliculum poorly developed or absent Icelus spiniger (Fig. 83) 16b. Sulcus straight anteriorly. Colliculum well developed and prominent Icelus canaliculatus (Fig. 84) 17a. Rostrum pointed, excisural notch absent or very shallow Radulinus asprellus (Fig. 85) 17b. Rostrum blunt, excisural notch obvious Gymnocanthus galeatus (Fig. 86) 18a. Rostrum blunt Icelus spatula (Fig. 87) 18b. Rostrum pointed Icelinus borealis (Fig. 88) and Gymnocanthus tricuspis (Fig. 89) 16 19a. Dorsal margin smooth 20 19b. Dorsal margin with at least a few definite crenulations 21 20a. Central part of dorsal margin arched, antero- and posterodorsal margins concave. Texture like frosted glass. Posterior end of otolith thickened Rhamphocottus richardsoni (Fig. 90) 20b. Dorsal margin evenly curved, may be concave only at excisural notch. Texture not like frosted glass. Posterior end not thicker than rest of otolith Genus Artedius (Figs. 91, 92) 21a. Both dorsal and ventral margins crenulate 22 21b. Dorsal margin crenulate, ventral margin smooth 23 22a. Postcaudal trough generally prominent except in very small specimens. Surface, especially on lateral side, rough and/or bulbous Genus Hemilepidotus (Figs. 93, 94, 95) 22b. Postcaudal trough absent. Surface smooth Genus Myoxocephalus (Figs. 75, 76, 77) 23a. Dorsal margin with a few broad crenulations 24 23b. Dorsal margin with fairly numerous crenulations 26 24a. Rostrum short, 15-20% of otolith length, or not distinguishable 25 24b. Rostrum long, 30% or more of otolith length Enophrys sp. (Fig. 97A) 25a. Height of otolith about 60% of its length Icelus canaliculatus (Fig. 84) 25b. Height of otolith about 50% of its length Enophrys bison (Fig. 97) 26a. Crista superior present along almost entire dorsal edge of sulcus Enophrys diceraus (Fig. 96) 26b. Crista superior either virtually absent or well developed only on anterior or posterior half of sulcus 27 27a. Crista superior poorly developed, virtually absent (Genus Triglops) 29 27b. Crista superior well developed on either anterior or posterior half of sulcus 28 28a. Crista superior well developed on anterior half of sulcus Leptocottus armatus (Fig. 98) 28b. Crista superior well developed on posterior end of sulcus Megalocottus platycephalus (Fig. 99) 29a. Excisural notch prominent Triglops scepticus (Fig. 100) 29b. Excisural notch poorly developed, anterodorsal margin of otolith not or only slightly indented 30 17 30a. Tip of rostrum broadly rounded, slightly upturned. Height of otolith 45% or less of its length . . . Triglops forficata (Fig. 101) 30b. Tip of rostrum more or less pointed, not upturned. Height of otolith 48%) or more of its length 31 31a. Posterior end broadly rounded (may show one or two crenulations), notably broader than ante- rior point Triglops pingeli (Fig. 102) 31b. Posterior end pointed, similar to anterior point Triglops macellus (Fig. 103) FAMILY AGONIDAE la. Longitudinal axis distinctly curved when viewed from above 2 lb. Longitudinal axis straight or nearly so 3 2a. Postcaudal trough deep and obvious Agonus acipenserinus (Fig. 104) 2b. Postcaudal trough shallow or absent Occella dodecaedron (Fig. 105) and 0. verrucosa (Fig. 106) 3a. Otolith notably thicker near ventral edge than near dorsal edge. Medial side flat 4 3b. Otolith of nearly uniform thickness. Both sides of similar curvature 5 4a. Rostrum well defined. Dorsal area rises abruptly from base of rostrum or they are separated by a notch and the colliculum is bulbous . . . .Bathyagonus nigripinnis (Fig. 107) and B. pentacanthus (Fig. 108) 4b. Rostrum not clearly separated from margin of dorsal area. If separated by a notch, the collicu- lum is absent or concave Bathyagonus infraspinatus (Fig. 109) and B. alascanus (Fig. 110) 5a. Height of otolith less than 45% of its length Anoplagonus inermis (Fig. Ill) 5b. Height of otolith more than 45% of its length 6 6a. Both dorsal and ventral margins smooth 7 6b. Dorsal margin and sometimes ventral margin crenulate 8 7a. No postcaudal trough Pallasina barbata (Fig. 112) 7b. Postcaudal trough present, prominent, reaches posterior margin Hypsagonus quadricornis (Fig. 113) 8a. Postcaudal trough obvious, reaches posteroventral margin of otolith. No dorsal branch to postcaudal trough Sarritor frenatus (Fig. 114) 8b. Postcaudal trough shallow, divided into channels to posteroventral and posterodorsal mar- gins, the dorsal branch more obvious than the ventral Sarritor leptorhynchus (Fig. 115) 18 FAMILY CYCLOPTERIDAE Because of the large number of species in this family, the difficulties involved in identifying them accurately, and the small amount of material available, the members of this group are not keyed out to species. Such reliably identified material as has been available has been illustrated. la. Height of otolith less than 65% of its length Genus Liparis (Figs. 121-124) lb. Height of otolith more than 70% of its length 2 2a. Rostrum present, distinct Genus Careproctus (Figs. 118-120) 2b. No rostrum 3 3a. Margins very smooth. Thickness of otolith more than 43% of its height. Otolith dense, opaque, porcelainous Genus Eumicrotremus (Fig. 116) 3b. Margins roughened. Thickness of otolith less than 40% of its height. Otolith translucent, glassy Genus Nectoliparis (Fig. 117) PLEURONECTIFORMES The otoliths of pleuronectiform fishes show distinct differences between the right and the left otoliths. The sulcus of the left otolith always shows a small cauda and a large ostium separated by a distinct collum, while in the right otolith the two portions are nearly equal or are not, or but scarcely, separated. In some species, the right and left otoliths are of different shapes. For the majority of species included here, both the right and left otoliths will key out to the same couplets, in which differences are described (e.g., couplets 13-15 below). Where marked differences exist between right and left otoliths, each is keyed out separately (e.g., Liopsetta glacialis: right, couplet 5; left, couplet 10). la. Otolith very thin and delicate, flat to slightly concave on medial side, usually a raised center on both sides. Shape highly variable, larger ones with deeply incised margins Reinhardtius hippoglossoides (Fig. 125) lb. Not as in la 2 2a. Margins notably smooth except for a small posterodorsal notch. Medial surface flat, lateral sur- face a smooth dome. Sulcus a shallow, oval pit with undeveloped cristae Citharichthys sordidus (Fig. 126) 2b. Margins various, but usually at least a few irregularities, indentations, or projections. Me- dial surface usually slightly rounded, lateral surface concave or irregularly convex. Sulcus with cristae present 3 3a. Outline of otolith resembles a slice of bread > 1 4 3b. Outline of otolith not as in 3a 7 4a. Medial side flat or nearly so 6 4b. Medial side convex 5 5a. Otolith thin, its thickness less than 20% of its length Liopsetta glacialis (right) (Fig. 127B) 5b. Otolith more robust, its thickness more than 20% of its length Hippoglossoides robustus (Fig. 128) and Isopsetta isolepis (Fig. 129) 19 6a. Axis of sulcus parallel with dorsal margin of otolith Limanda proboscidea (Fig. 130) 6b. Axis of sulcus slants ventrad anteriorly Glyptocephalus zachirus (Fig. 131) 7a. A distinct, well-defined notch in anterodorsal margin, usually about 90° or less 8 7b. Notch absent or poorly defined; if present, usually broader than 90° 9 8a. Notch V-shaped, forming angle of 60° -90°. Posterodorsal corner of otolith square or round- ed, without a distinct projection. Height of dorsal area averages 90% (87-107%) of height of ventral area. Ventral margin sometimes irregular, but not lobed Hippoglossus stenolepis (Fig. 132) 8b. Notch usually forms angle of 90° or more. Posterodorsal corner of otolith usually with a dis- tinct projection. Height of dorsal area averages 86% (75-93%) of height of ventral area. Ven- tral margin lobate Platichthys stellatus (Fig. 133) 9a. Dorsal margin rounded, usually with almost same curvature as ventral margin. Otolith oval to almond-shaped 10 9b. Dorsal margin straight or nearly so, often indented. Otolith not oval or almond-shaped 12 10a. Posterior end of otolith much thicker than anterior end. Dorsal margin crenulate Liopsetta glacialis (left) (Fig. 127 A) 10b. Both ends of otolith about the same thickness. Dorsal margin not crenulate 11 11a. Height of otolith 65% (62-67%) of its length. Otolith large, may exceed 15 mm long. Otolith thin, one of 8-mm length will be less than 1 mm thick Atheresthes stomias (Fig. 134) lib. Height of otolith 58% (56-62%) of its length. Otolith small, rarely longer than 8 mm, and thick, an 8-mm otolith will be more than 1.5 mm thick Microstomias pacificus (Fig. 135) 12a. Anterior end of otolith broadly rounded 13 12b. Anterior end of otolith more or less tapered 16 13a. Left sulcus shorter than 75% of height of otolith. Right otolith thicker posteriorly than ante- riorly. Right sulcus generally shorter than 65% of otolith height 14 13b. Left sulcus longer than 75% of height of otolith. Right otolith not much thicker posteriorly than anteriorly. Right sulcus generally longer than 65% of otolith height 15 14a. Posterodorsal corner sharp, usually forming an angle of 90°-95°. Ventral margin of otolith al- most always crenulate or lobate Pleuronectes quadrituberculatus (Fig. 136) 14b. Posterodorsal corner not particularly sharp, generally forming an angle of 110° or more. Ven- tral margin of otolith smooth to irregular, rarely crenulate Hippoglossoides elassodon (Fig. 137) 20 15a. Ventral margin of otolith nearly straight. Dorsal and ventral margins of sulcus parallel Psettichthys melanostictus (Fig. 138) 15b. Ventral margin of otolith rounded. Dorsal and ventral margins of sulcus flare apart ante- riorly Limanda aspera (Fig. 139) 16a. Dorsal margin of otolith usually with a prominent notch near its middle. Lateral surface with a prominent, deep groove opening into the notch, groove present even when notch is absent 18 16b. No notch on dorsal margin of otolith. Groove on lateral surface, if present, broad and shal- low, not prominent 17 17a. Greatest height of otolith near middle of its length Hippoglossus stenolepis (Fig. 132) 17b. Greatest height of otolith near posterior end Lepidopsetta bilineata (Fig. 140) 18a. Margins of otolith usually lobate or crenulate. Dorsal margin of otolith parallel to sulcus. Poste- rior margin of otolith usually rounded Parophrys vetulus (Fig. 141) 18b. Margins of otolith usually smooth, rarely lobate. Dorsal margin diverges from sulcus posterior- ly. Posterior margin of otolith nearly always straight Eopsetta jordani (Fig. 142) ACKNOWLEDGMENTS This study was supported by the Bureau of Land Management through interagency agreement with the National Oceanographic and Atmospheric Administra- tion, under which a multiyear program responding to needs of petroleum development on the Alaskan con- tinental shelf was managed by the Outer Continental Shelf Environmental Assessment Program office. Some specimens were obtained from trawling cruises made by NOAA and National Marine Fisheries Service vessels as part of the overall program. Additional material was lent by Jack Lalanne and Hiro Kajimura, National Marine Fisheries Service, Seattle; by Kathy Frost and Lloyd Lowry, Alaska Department of Fish and Game, Fair- banks; and by the University of Alaska Museum Fish Collection. Specimens of 66 of the 142 species included were lent by John E. Fitch, California Department of Fish and Game, Long Beach. In addition, John E. Fitch has given most generously of his time and expertise and has reviewed the several drafts of the manuscript. My as- sistants, Edmond Murrell and Sverre Pedersen, then graduate students in the Division of Life Sciences, University of Alaska, labored conscientiously in extract- ing and preparing otoliths and other skeletal materials and prepared preliminary versions of several family keys. Frost, Fitch, Lowry, Murrell, and Pedersen all tested the accuracy of the keys. Timothy Sczawinski made the drawings. I am most grateful to all these people and in- stitutions for their help and support. Faults or errors in the keys are, however, solely my responsibility. LITERATURE CITED BAILEY, R. M., J. E. FITCH, E. S. HERALD, E. A. LACHNER, C. C. LINDSEY, C. R. ROBINS, and W. B. SCOTT. 1970. A list of common and scientific names of fishes from the United States and Canada. 3d ed. Am. Fish. Soc. Spec. Publ. 6, 150 p. FRIZZELL, D. L., and J. H. DANTE. 1966. Otoliths of some early Cenozoic fishes of the Gulf Coast. J. Palaeontol. 39:687-718. QUAST, J. C, and E. L. HALL. 1972. List of fishes of Alaska and adjacent waters with a guide to some of their literature. U.S. Dep. Commer., NOAA Tech. Rep. NMFS SSRF-658, 47 p. 21 ANTI- ROSTRUM- EXCISURAL NOTCH DORSAL AREA r-COLLUM EXCISURA MAJOR v COLLICULUM VENTRAL AREA EXCISURA MINOR ROSTRUM LENGTH OF ROSTRUM HEIGHT OF ROSTRUM Plate I. — Diagrams of medial sides of right otoliths, showing major features and measurements. 22 Plate II. — Figures 1 through 16. Medial side (except as noted) of oto Osmeridae, and Gadidae. Figures: 1. — Antimora microlepis — Longfi herring. Right otolith 4.1 mm long. 3. — Lyconectes aleutensis — Dwar wrymouth. Right otolith 8.5 mm long. 5.—Delolepis gigantea— Giant w Pacific sandlance. Left otolith 1.3 mm long. 7. — Mallotus villosus — C Right otolith 4.4 mm long. 9. — Hypomesus pretiosus — Surf smelt. Righ otolith 4.0 mm long. 11. — Spirinchus thaleichthys—Longrm smelt. R otolith 2.5 mm long. 13. — Gadus macrocephalus — Pacific cod. Right o Left otolith 15.0 mm long. 15. — Merluccius productus — Pacific hake. L side of right otolith 6.8 mm long. B. Lateral side of same otolith. liths of Antimoridae, Clupeidae, Cryptacanthodidae, Ammodytidae, n cod. Left otolith 10.4 mm long. 2. — Clupea harengus pallasi — Pacific f wrymouth. Right otolith 4.5 mm long. 4. — Delolepis gigantea — Giant rymouth. Right otolith 7.9 mm long. 6. — Ammodytes hexapterus — apelin. Left otolith 2.4 mm long. 8. — Thaleichthys pacificus— Eulachon. t otolith 5.0 mm long. 10. — Osmerus eperlanus — Rainbow smelt. Right ight otolith 4.5 mm long. 12. — Hypomesus olidus— Pond smelt. Right tolith 14.0 mm long. li.—Theragra chalcogramma— Walleye pollock, eft otolith 16.0 mm long. 16. — Boreogadus saida— Arctic cod. A. Medial 23 Plate III. — Figures 17 through 31. Medial side (except as noted) of otoliths of Gadidae, Zoarcidae, Trichodontidae, and Bathymasteridae. Figures: 17. — Microgadus proximus — Pacific tomcod. A. Medial side of right otolith 12.3 mm long. B. Lateral side of same otolith. 18. — Eleginus gracilis — Saffron cod. Left otolith 11.2 mm long. 19. — Embryx crotalina — Snakehead eelpout. Right otolith 2.9 mm long. 20. — Bothrocara brunneum — Twoline eelpout. A. Right otolith 5.0 mm long. B. Cross section. 21. — Bothrocara pusillum — Alaska eelpout. Right otolith 2.0 mm long. 22. — Bothrocara molle — Soft eelpout. Left otolith 1.9 mm long. 23. — Lycodopsis pacifica — Blackbelly eelpout. Right otolith 4.5 mm long. 24. — Lycodes palearis — Wattled eelpout. Right otolith 5.0 mm long. 25. — Lycodes brevipes — Shortfin eelpout. Right otolith 5.0 mm long. 26. — Lycodes diapterus — Black eelpout. Right otolith 5.7 mm long. 27. — Trichodon trichodon — Pacific sandfish. Right otolith 4.3 mm long. 28. — Arctoscopus japonicus — Sailfin sandfish. Right otolith 6.0 mm long. 29. — Ronquilus jordani — Northern ronquil. Right otolith 5.3 mm long. 30. — Bathymaster signatus — Searcher. Right otolith 5.0 mm long. 31. — Bathymaster caeruleofasciatus — Alaska ronquil. Left otolith 8.0 mm long. 24 Plate IV.— Figures 32 through 46. Medial side of otoliths of Stichaeidae Lumpenella longirostris — Longsnout prickleback. Left otolith 3.6 mm I long. 34. — Poroelinus rothrocki — Whitebarred prickleback. Right oto back. Right otolith 2.8 mm long. 36. — Lumpenus fabricii — Slender ee prickleback. Right otolith 3.5 mm long. 38. — Stichaeus punctatus — Penpoint gunnel. Right otolith 2.2 mm long. 40. — Pholis ornata — Sa ocellatus — Wolf-eel. Right otolith 4.3 mm long. 42. — Anarhichas orie altivelis — Longspine thornyhead. Right otolith 12.0 mm long. 44. — long. 45. — Sebastes entomelas — Widow rockfish. Right otolith 17.0 m 17.0 mm long. Pholididae, Anarhichadidae, and Scorpaenidae. Figures: 32. — ong. 33. — Lumpenus maculatus — Daubed shanny. Right otolith 1.9 mm lith 2.9 mm long. 35. — Acantholumpenus mackayi — Pighead prickle- lblenny. Right otolith 2.3 mm long. 37. — Lumpenus sagitta — Snake Arctic shanny. Right otolith 3.2 mm long. 39. — Apodichthys flavidus — ddleback gunnel. Right otolith 2.0 mm long. 41. — Anarrhichthys ntalis — Bering wolffish. Right otolith 3.4 mm long. 43. — Sebastolobus Sebastolobus alascanus — Shortspine thornyhead. Right otolith 12.0 mm m long. 46. — Sebastes brevispinis — Silvergray rockfish. Right otolith 25 Plate V. — Figures 47 through 59. Medial side of otoliths of Scorpaenidae. Figures: 47. — Sebastes proriger — Redstripe rockfish. Right otolith (3.0 mm long. 48. — Sebastes caurinus — Copper rockfish. Right otolith 20.5 mm long. 49. — Sebastes mystinus — Blue rockfish. Right otolith 16.0 mm long. 50. — Sebastes maliger — Quillback rockfish. Right otolith 14.5 mm long. 51. — Sebastes melanostomus — Blackgill rockfish. Right otolith 20.1) mm long. 52. — Sebastes aurora — Aurora rockfish. Right otolith 12.0 mm long. 53. — Sebastes ciliatus — Dusky rockfish. Right otolith 13.0 mm long. 54. — Sebastes melanops — Black rockfish. Right otolith 17.0 mm long. 55. — Sebastes polyspinis — Northern rockfish. Right otolith 14.0 mm long. 56. — Sebastes babcocki — Redbanded rockfish. Right otolith 18.0 mm long. 57. — Sebastes zacentrus — Sharpchin rockfish. Right otolith 13.0 mm long. 58. — Sebastes borealis — Shortraker rockfish. A. Right otolith 23.0 mm long. B. Posterior end of another otolith to show typical projections. 59. — Sebastes crameri — Darkblotched rockfish. Right otolith 17.0 mm long. 2f, Plate VI. — Figures 60 through 76. Medial side of otoliths of Scorpaenidae, Anoplopomatidae, Hexagrammidae, and Cottidae. Figures: 60. — Sebastes variegatus — Harlequin rockfish. Right otolith 6.8 mm long. 61. — Sebastcs alutus — Pacific ocean perch. Right otolith 14.2 mm long. 62. — Sebastes aleutianus — Rougheye rockfish. Right otolith 14.5 mm long. 63.— Sebastes ruberrimus — Yelloweye rockfish. Right otolith 22.0 mm long. M.—Erilepis zonifer— Skilfish. Right otolith 7.5 mm long. 65.— Anoplopoma fimbria— Sablefish. Right otolith 10.4 mm long. 66. — Pleurogrammus monopterygius — Atka mackerel. Right otolith 5.0 mm long. 67. — Ophiodon elongatus — Ling cod. Right otolith 5.8 mm long. 68. — Hexagrammos lagocephalus — Rock greenling. Right otolith 5.7 mm long. 69. — Hexagrammos stelleri — Whitespotted greenling. Right otolith 2.2 mm long. 70. — Hexagrammos octogrammus — Masked greenling. Right otolith 4.5 mm long. 71. — Hexagrammos decagrammus — Kelp greenling. Right otolith 6.5 mm long. 72. — Dasycottus setigei — Spinyhead sculpin. Right otolith 8.9 mm long. 73. — Psychrolutes paradoxus — Tadpole sculpin. Right otolith 2.0 mm long. 74. — Myoxocephalus quadricornis — Fourhorn sculpin. Right otolith 8.2 mm long. 75. — Myoxocephalus polyacanthocephalus — Great sculpin. Right otolith 8.5 mm long. 76. — Myoxocephalus jaok — Plain sculpin. Right otolith 10.5 mm long. 27 Plate VII.— Figures 77 through 92. Medial side of otoliths of Cottidae otolith 8.6 mm long. IH.—Malacocottus kincaidi — Blackfin sculpin. R name. Right otolith 1.4 mm long. 80. — Blepsias bilobus — Crested scul sculpin. Right otolith 1.9 mm long. 82. — Hemitripterus bolini — Bigmo name. Right otolith 4.7 mm long. 84. — Icelus canaliculatus — No comm sculpin. Right otolith 4.4 mm long. 86. — Gymnocanlhus galeatus — Spatulate sculpin. Right otolith 4.3 mm long. 88. — Icelinus borealis — tricuspis — Arctic staghorn sculpin. Right otolith 3.8 mm long. 90. — 91. — Artedius harringtoni — Scalyhead sculpin. Right otolith 2.7 mm lo long. Figures: 77 .—Myoxocephalus scorpius— Shorthorn sculpin. Right ight otolith 8.5 mm long. 79. — Nautichthys robustus — No common pin. Right otolith 1.8 mm long. 81. — Blepsias cirrhosus — Silverspotted uth sculpin. Right otolith 4.5 mm long. 83. — Icelus spiniger — No common on name. Right otolith 6.5 mm long. 85. — Radulinus asprellus — Slim Armorhead sculpin. Right otolith 8.5 mm long. 87.— Icelus spatula — Northern sculpin. Right otolith 3.8 mm long. 89. — Gymnocanthus Rhamphocottus richardsoni — Grunt sculpin. Right otolith 2.0 mm long, ng. 92.— Artedius fenestralis— Padded sculpin. Right otolith 4.6 mm 2H Plate VIII.— Figures 93 through 107. Medial side of otoliths of Cottidae and Agonidae. Figures: M.—Hemilepidotus hemilepidotus— Red Irish lord. Right otolith 6.0 mm long. M.—Hemilepidotus jordani— Yellow Irish lord. Right otolith 4.0 mm long. 95.—Hemilepidotus spinosus — Brown Irish lord. Right otolith 9.0 mm long. 96. — Enophrys diceraus — Antlered sculpin. Right otolith 9.5 mm long. 97. — Enophrys bison— Buffalo sculpin. Right otolith 9.5 mm long. 97A.— Enophrys sp. Right otolith 3.4 mm long. 9$.—Leptocottus armatus— Pacific staghorn sculpin. Right otolith 9.5 mm long. 99. — Megalocottus platycephalus — Belligerent sculpin. Right otolith 7.2 mm long. 100. — Triglops scepticus — Spectacled sculpin. Right otolith 7.0 mm long. 101. — Triglops /br/icata— Scissortail sculpin. Right otolith 5.8 mm long. 102.— Triglops pingeli— Ribbed sculpin. Right otolith 4.3 mm long. 103.— Triglops macellus— Roughspine sculpin. Right otolith 6.8 mm long. 104. — Agonus acipenserinus— Sturgeon poacher. Right otolith 3.5 mm long. 105. — Occella dodecaedron — Bering poacher. Right otolith 4.8 mm long. 106.— Occella verrucosa — Warty poacher. Right otolith 3.9 mm long. 107. — Bathyagonus nigripinnis — Blackfin poacher. Right otolith 4.9 mm long. 29 Plate IX. — Figures 108 through 123. Medial side of otoliths of Agonidae and Cyclopteridae. Figures: 108. — Bathyagonus pentacanthus — Bigeye poacher. Right otolith 3.7 mm long. 109. — Bathyagonus infraspinatus — Spinycheek starsnout. Right otolith 3.4 mm long. 110. — Bathyagonus alascanus— Gray starsnout. Right otolith 3.2 mm long. 1 11. — Anoplagonus inermis — Smooth alligatorfish. Right otolith 2.8 mm long. 112. — Pallasina barbata — Tubenose poacher. Right otolith 1.5 mm long. 113. — Hypsagonus quadricornis — Fourhorn poacher. Right otolith 2.2 mm long. 114. — Sarritor frenatus — Sawback poacher. Right otolith 7.1 mm long. 115. — Sarritor leptorhynchus — Longnose poacher. Right otolith 5.7 mm long. Wti.—Eumierotremus orbis — Pacific spiny lumpsucker. Right otolith 1.2 mm long. 117. — Nectoliparis pelagicus — Tadpole snailfish. Right otolith 0.7 mm long. 118. — Careproctus sp. Right otolith 2.9 mm long. 119. — Careproctus furcellus — No common name. Right otolith 4.0 mm long. 120. — Careproctus melanurus — Blacktail snailfish. Right otolith 3.5 mm long. 121. — Liparis pulchellus — Showy snailfish. Right otolith 3.0 mm long. 122. — Liparis dennyi — Marbled snailfish. Right otolith 2.9 mm long. 123. — Liparis liparis — Striped seasnail. Right otolith 4.1 mm long. 30 Plate X.— Figures 124 through 133. Medial side of otoliths of Cyclopterid ae, Bothidae, and Pleuronectidae. Figures: 124.— Liparis gibbus— No common name. Right otolith 2.2 mm long. 125.— Reinhardtius hippoglossoid.es— Greenland halibut. A. Left otolith 2.4 mm long. B. Right otolith 4.5 mm long. C. Right otolith 6.5 mm long. 126.— Citharichthys sordid us— Pacific sanddab. Right otolith 8.2 mm long. 127.— Liopsetta glacialis — Arctic flounder. A. Left otolith 6.8 mm long. B. Right otolith 4.7 mm long. 128. —Hippoglossoides robustus — Bering flounder. Right otolith 5.0 mm long. 129.— Isopsetta isolepis — Butter sole. Right otolith 5.8 mm long. 130. — Limanda proboscidea — Longhead dab. Left otolith 4.2 mm long. 131. — Glyptocephalus zachirus — Rex sole. Left otolith 4.9 mm long. 132.— Hippoglossus stenolepis — Pacific halibut. Right otolith 6.4 mm long. 133.— Platichthys stellatus— Starry flounder. Right otolith 7.2 mm long. 31 Plate XI. — Figures 134 through 142. Medial side of otoliths of Pleuronectidae. Figures: 134. — Atheresthes stomias — Arrowtooth flounder. Right otolith 8.0 mm long. 135. — Microstomas pacificus — Dover sole. Right otolith 6.5 mm long. 13fi. — Pleuronectes quadrituberculatus — Alaska plaice. A. Left otolith 8.0 mm long. B. Right otolith 8.0 mm long. 137. — Hippoglossoid.es elassodon — Flathead sole. Left otolith 7.7 mm long. 138. — Psettichthys melanostictus — Sand sole. Left otolith 5.0 mm long. 139. — Limanda aspera — Yellowfin sole. Left otolith 7.3 mm long. 140. — Lepidopsetta bilineata — Rock sole. Left otolith 6.1 mm long. 141. — Parophrys vetulus — English sole. A. Left otolith 5.9 mm long. B. Right otolith 5.8 mm long. 142. — Eopsetta jordani — Petrale sole. Left otolith 7.0 mm long. 32 388. Proceedings of the first U.S. -Japan meeting on aquaculture at Tokyo, Japan, October 18-19, 1971. William N. Shaw (editor). (18 papers, 14 authors.) February 1974, iii + 183 p. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington. DC. 20402. 389. Marine flora and fauna of the northeastern United States. Crustacea: Decapoda. By Austin B. Williams. April 1974, iii + 50 p., Ill figs. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington. D.C. 20402. 390. Fishery publications, calendar year 1973: Lists and indexes. By Mary Ellen Engett and Lee C. Thorson. September 1974, iv + 14 p., 1 fig. For sale bv the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 391. Calanoid copepods of the genera Spinucalanus and Mimncalanus from the central Arctic Ocean, with a review of the Spinocalanidae. By David M. Damkaer. June 1975, x + 88 p., 225 figs.. 4 tables. For sale bv the Superintendent of Documents, U.S. Government Printing Office, Washington. D.C. 20402. 392. Fishery publications, calendar year 1974: Lists and indexes. By Lee C. Thorson and Mary Ellen Engett. June 1975, iv + 27 p., 1 fig. 393 Cooperative Gulf of Mexico estuarine inventory and study — Texas: Area description. By Richard A. Diener. September 1975, vi + 129 p., 55 figs., 26 tables. 394. Marine Flora and Fauna of the Northeastern United States. Tar- digrade Bv Leland W. Pollock. May 1976, iii + 25 p.. figs. For sale by the Superintendent of Documents. U.S. Government Printing Office, Washington. D.C. 20402. 395. Report of a colloquium on larval fish mortality studies and their relation to fishery research. January 1975. By John R. Hunter. May 1976, iii + 5 p. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 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