734 \KU R. !.HiTM ^^f.^'OQ!AL LIBRARY &- CC'CUfU-JsTAiiON CtNfr.R ICLARM A.i ^ 0) VL / VKt^*^ °"C0. C \ o .V^ NpAA Technical Report NMFS SSRF-734 Escape of King Crab, Paralithodes camtschatica, From Derelict Pots William L. High and Donald D. Worlund May 1979 MAR 2 51993 '! FXCH\NGg -iological Laboratory/ Jcft.-ringraphic Institution MAY 6 1V% Woods Hole. MA 02543 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atnnospheric Adnninistration National Marine Fisheries Service NOAA TECHNICAL REPORTS National Marine Fisheries Service, Special Scientific Report — Fisheries The major responsibilities of the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and geographic distribution of fisher>' resources, to understand and predict fluctuations in the quantity and distribution of these resources, and to establish levels for optimum use of the resources. NMP'S is also charged with the development and implementation of policies for managing national fishing grounds, development and enforcement of domestic fisheries regulations, surveillance of foreign fishing off I'nited States coastal waters, and the development and enforcement of international fishery agreements and policies. NMF.S also assists the fishing industry through marketing service and economic analysis programs, and mortgage insurance and vessel construction subsidies. It collects, analyzes, and publishes statistics on various phases of the industry. The Special Scientific Report— Fisheries series was established in 1949. The series carries reports on scientific investigations that document long-term omiinuing programs of NMFS. or intensive scientific reports on studies of restricted scope. The reports may deal with applied fishery problems. The series is also used as a medium for the publication of bibliographies of a specialized scientific nature. NOAA Technical Re[X)rts NMFS SSRF 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 notedl from 1)82.5. Technical Information Division. Environmental Science Information Center. NOAA. Washington, D.C. 20235. Recent SSRFs are: 649. Distribution of forage of skipjack tuna {Euthynnus pelamis) in the eastern tropical Pacific. By Maurice Blackburn and Michael Laurs. ■January 1972. iii + 16 p.. 7 figs.. 3 tables. For sale by the .Superintendent of Documents. 11. S. Government Printing Office. Washington. D.C. 20402. fi61 A review of the literature on the development of skipjack tuna fisheries in the central and western Pacific Ocean. By Frank J. Hester and Tamio (.)tsu. January !973. iii + 13 p.. 1 fig. For sale by the Superintendent of D<)cumen(s. U.S. Government Printing Office. Washington. D.C. 20402. (>50. Effects of some antioxidants and EDTA on the development of ran- cidity in Spanish mackerel iScambernmorus maculatus) during frozen storage. By Robert N. Farragut. February 1972. iv -f 12 p.. 6 figs.. 12 tables. For sale b\' the Superintendent of Documents. U.S. Government Printing Office. Washmgton. DC. 20402. 6.51. The effect of premortem stress, holding temperatures, and freezing on the biochemistry and quality of skipjack tuna. By Ladeli Crawford. April 1972. iii + 2.3 p.. 3 figs.. 4 tables. For sale by the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 653. The use of electricity in conjunction with a 12.5-meter (Headrope) Gulf-of-Mexico shrimp trawl in Lake Michigan. By James E. Ellis March 1972. iv -f 10 p.. 1 1 figs.. 4 tables. For t.ale by the .Superintendent of Documents, U.S. Government Printing Office, Washington. D.C. 20402. 6.54. An electric detector system for recovering internally tagged menhaden, genus Hreiimrtia. By R. O. Parker. Jr. February 1972. iii + 7 p.. 3 figs.. 1 app. table. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. DC. 20402. 655. Immobilization of fingerling salmon and trout by decompression. By Doyle F. Sutherland. March 1972. iii + 1 p., 3 figs.. 2 tables. For sale by the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 6.56. The calico scallop. Argopecten gihhus. Bv Donald M. Allen and T. J. Costello. May 1972. iii -f 19 p.. 9 figs.. 1 table. For sale by the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 662. .Seasonal distribution of tunas and billfishes in the Atlantic. By John P. Wise and Charles W. Davis. January 1973. iv + 24 p.. 13 figs.. 4 tables. For sale by the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 663. Fish larvae collected from the northeastern Pacific Ocean and Puget Sound during April and May 1967. By Kenneth D. Waldron. December 1972. iii + 16 p.. 2 figs.. 1 table. 4 app. tables. For sale by the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 664. Tagging and tag-recovery experiments with Atlantic menhaden. Hri'iiiiortta tyrannus. By Richard L. Kroger and Robert L. Dryfoos. December 1972. iv -^ 11 p.. 4 figs.. 12 tables. For sale by the Superinten- dent of Documents. U.S. Government Printing Office, Washington, D.C. 20402. 665. Larval fish survey of Humbolt Bay. California. By Maxwell B. Eldrige and (^harles F. Bryan. December 1972. iii + 8 p.. 8 figs.. 1 table. For sale bv the .Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 666. Distribution and relative abundance of fishes in Newport River. North Carolina. By William R. Turner and George N. Johnson. September 1973. iv + 23 p.. 1 fig.. 13 tables. For sale by the Superinten- dent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 667. An analysis of the commercial lobster {Homarus americanus) fishery along the coast of Maine. August 1966 through December 1970. By James C. Thomas. June 1973. v -h .57 p., 18 figs.. 11 tables. For sale by the Superintendent of Documents. L^.S. Government Printing Office, Washington. D.C. 20402. 657. Making fish protein concentrates by enzymatic hydrolysis. A status report on research and .some processes and products studied by NMFS. By Malcolm B. Hale, November 1972. v + 32 p.. 15 figs.. 17 tables. 1 app, table. For sale by the Superintendent of Documents, U.S. GovernmenI Printing Office. Washington. DC. 20402. 6.58. List of fishes of Alaska and adjacent waters with a guide to some of their literature By Jay C, Quast and Elizabeth L. Hall. July 1972. iv -h 47 p. For sale by the .Superintendent of Documents. Lf.S, Government Printing Office. Washington. DC. 20402. 6.59. The Southeast Fisheries Center bionumeric code. Part 1: Fishes. By Harvey R. Bullis. Jr.. Richard B. Roe. and .ludith C. Gatlin. July 1972. xl + 95 p.. 2 figs. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. D.C. 20402. 660. A freshwater fish electro-motivator IFFEMl-its characteristics and operation. By James E. Ellis and Charles C. Hoopes. November 1972. iii + 11 p.. 2 figs. 668, An annotated bibliography of the cunner. Tautogotahrus adspersus (Wilbaum), By Fredric M, Serchuk and David W, Frame. May 1973. ii -t- 43 p. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. D.C. 20402. (i69. Subpoint prediction for direct readout meterological satellites. By L, E. Eher, August 1973. iii -t- 7 p., 2 figs.. 1 table. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. DC. 20402. 670. llnharvested fishes in the U.S. commercial fishery of western Lake Erie in 1969, By Harry D. Van Meter. July 1973. iii -i- 11 p., 6 figs., 6 tables. For sale by the Superintendent of Documents. U.S. Government Printing Office. WashingKm. D.C. 20402. 671. Coa.stal upwelling indices, west coast of North America, 1946-71. By Andrew Bakun June 1973. iv -I- 103 p., 6 figs., 3 tables. 45 app. figs. For sale by the .Supermtendent of Documents. U.S. Government Printing Office. Washington. DC, 20402 (■(inlinued iin inside bark cover NOAA Technical Report NMFS SSRF-734 MMOsp^ "'"^'H^^^'-'" Escape of King Crab, Paralithodes camtschatica, From Derelict Pots William L. High and Donald D. Woriund May 1979 m . 6 1996 Woods Hole, MA 02543 U.S. DEPARTMENT OF COMMERCE Juanita M. Kreps. Secretary National Oceanic and Atmospheric Administration Richard A. Frank, Administrator Terry L. Leitzeii, Assistant Administrator for 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. COCUMGNTAriON CENTER ICLARM CONTENTS Page Introduction 1 History of the problem 1 Magnitude of pot loss 2 Experimental design 3 Materials and methods 3 Description of pots 3 Selecting, handling, and tagging crab 3 Unbaited pot experiments 5 Box shaped pots 5 Fiberglass pyramid pots 5 Radical pyramid pots 5 Conical snow crab pots 5 Crowding experiment 5 Baited pot experiment 5 Confined crab viability experiment 5 Incidental catch observations 6 Results 7 Escape from standard pots 7 Effect of bait or dead crab 8 Mortality in pots 8 Tag returns 9 Viability of escaped crab 9 Incidental catches 9 Summary and conclusions 10 Acknowledgments 11 Literature cited 11 Figures 1. This abandoned Japanese-type snow crab pot, recovered 3 mo after close of the commercial fishing season, contained 12 king crab and 14 snow crab 2 2. Dimensions and weights for crab pots used in the experiments 4 3. Average escapement retransformed to percent for small and large king crab from standard pots 8 4. King crab escapement from baited and unbaited pots after various soak intervals 8 5. Entry of new king crab into pots containing herring, dead crab, or no bait 9 Tables 1. Eicap)ement and soak time of undersize and legal-size king crab for various pot types 6 2. Escapement of legal-size king crab from standard pots 7 3. Escapement of undersize king crab from standard pots 7 4. Observed mortality in pots at retrieval for tagged king crab confined in pots of various designs or configurations 10 5. Combined return of tags from undersize and legal-size king crab that escaped from each 1974 experi- ment during various soak intervals 11 6. Combined return of tags from undersize and legal-size king crab that escaped from each 1975 experi- ment during various soak intervals 11 ui Escape of King Crab, Paralithodes camtschatica. From Derelict Pots WILLIAM L. HIGH and DONALD D. WORLUND' ABSTRACT Loss of U)7( per season of pots (traps) in the Alaskan fishery for the king crab, Paralithodes camtschatica. has raised the question of possible loss of crabs and fishes to the derelict, or lost, pots which continue to fish. We conducted a series of experiments during 1974 and 1975 in which tagged king crab were placed in several types of pots and returned to the bottom (soaked) for periods of 1-lfl days. As controls, we released some tagged king crab in Chiniak Bay, Kodiak Island. Alaska. Tagged crab missing from the pots at time of recovery were credited with escape. The experiments demonstrated that 'J27f of undersize and 807f of legal-size king crab readily es- caped the derelict pots. Mortality among crab held in pots for various experiments ranged up to 12%. Crab that escaped within 1-4 days were recovered by commercial fishermen at about the same rate as those released in Chiniak Bay near the experiment site. However, those released after a 10- to l(i-day confinement were returned at a much lower rate. Some commercially valuable fishes — such as Pacific halibut, Hippoglossus stenolepis— were also caught in the experimental pots. INTRODUCTION King crab fishermen in Alaskan waters report losing about 10% of their pots (traps) per season as a result of various mishaps. Lost, or derelict, pots continue to at- tract crabs and other animals for sometime. Animals un- able to escape from derelict pots eventually die. Species most frequently taken with king crab pots include the king crab, genus Paralithodes; the snow (Tanner) crab, genus Chionoecetes; the Pacific halibut, Hippoglossus stenolepis; and the Pacific cod, Gadus macrocephalus. As part of an effort to estimate the mortality of crabs and other species in derelict pots, the National Marine Fisheries Service, in cooperation with the Alaska Depart- ment of Fish and Game, conducted several experiments during 1974 and 1975 in Chiniak Bay near Kodiak, Alaska. Our aim was to learn more about the signifi- cance of derelict pots on the king crab resource. Specif- ically, we wished to determine: 1) the rate of escape of undersize and legal-size king crab from four types of pots; 2) the effect of crowding upon escape; 3) the effect of baited pots and the presence of dead crab upon escape rate; and 4) the effects of confinement on subsequent recapture of tagged king crab. We did not simultaneously conduct independent tests to determine entry rates of crab into king crab pots. How- ever, crab entry would not be critical if our study were to show that all those entering would eventually escape. If destruction of animals was found to be significant, then it would be appropriate to equip king crab pots with a degradable panel, that is, a portion of the enclosure which would deteriorate rapidly and finally disintegrate when left in the sea unattended. Degradable panels (featuring web, secured by natural fibers) are already a standard part of sablefish, Anoplopoma fimbria, traps (Hipkins 1974) and have been proposed for king crab pots." However, the cost in time to fishermen to maintain degradable panels is significant; therefore, they should not be required unless the benefits justify the expense. HISTORY OF THE PROBLEM Although some king crab fishing by U.S. fishermen began just before the Second World War (1941-45), it was not until nearly 1960 that the fishery was well estab- lished. The peak catch of 159.2 million pounds by about 300 vessels was reached in 1966. Fishing effort has con- tinued to be high since 1965, but the catch has declined and was only 97.8 million pounds in 1975 (Rod Kaiser^). Concern for the possible detrimental effects of derelict pots has been expressed in several qufulers. Crab fisher- men reported occasionally retrieving lost pots contain- ing numerous crabs which they believed would die and attract other crabs, repeating the cycle until the trap was destroyed. Both crab and halibut fishermen observed that halibut often enter baited pots and are quickly at- tacked and killed by sand fleas (amphipods), ending up as bait within the pot for at least a short time. Scientists studying gear operations expressed concern because available evidence suggested that heavy steel- framed pots with synthetic enclosure webbing would re- main intact for some years. Occasionally, during research cruises, derelict pots were recovered which had apparently been submerged for 1 or more years. They 'Northwest and Alaska Fisheries Center. National Marine Fisheries Service, NOAA, 2725 Montlake Boulevard East, Seattle, WA 98112. =In 1976, the Alaska Board of Fisheries directed that after 1 July 1978, a degradable panel be placed in all king crab pots. 1976 Alaska Commer- cial Fishing Regulations. 1976-77 ed., p. 42. 'Rod Kaiser. Alaska Department of Fish and Game, Kodiak, AK 99615, pers. commun.. September 1976. contained numerous crabs and seemed to be in good working order. Interviews with fishermen revealed common causes of pot loss including: 1) buoyline breakage from chafing or entanglement in vessel propellers; 2) buoy puncture by sea lions; 3) pots carried into deeper water when tangled in gear such as trawls, longline, or other pots; and 4) buoyline entanglement during set, so line is too short and buoys are carried under the surface. MAGNITUDE OF POT LOSS The year 1960 was the beginning of rapid growth in U.S. king crab fishing. By 1964, about 270 vessels par- ticipated in the fishery. The number of pots fished varied greatly among vessels because of variations in vessel size and changing Alaska regulatory limits for pots fished per vessel. In the 1969-70 season, 354 vessels fished an aver- age of 70 [jots each (Rod Kaiser, see footnote 3). Fisher- men generally agree that about 10% of their pots are lost each season. Some vessels reported pot losses of up to 50%, but such losses were uncommon. To develop an estimated number of lost pots, we as- sume that 300 vessels fished an average of 60 pots each per year from 1960 to 1975. About 10%, or 27,000, of the 270,000 pots fished during the 15 yr may have been lost. Based upon the engineering longevity estimate of 15 yr for pots (Richard McNeely*), we can assume that many lost pots may still be fishing. The others would no longer catch crabs because of damage by fishing gear — such as trawl, longline, and other pots — or because of environ- mental conditions — such as pots settling into sand at shallow depths (Rearden 1976). Sea lions could also have damaged the pots. In view of those estimates, and from interviews with fishermen, we conclude that there are thousands of pots in fishing condition lying on commercial crab grounds. Occasional derelict pot recoveries confirm that crabs continue to enter them (Fig. 1). The problem of derelict pots, then, lies with the number of fishable pots and the mortality of crabs entering them. ■•Richard McNeely, Northwest and Alaska Fisheries Center, National Marine Fisheries Service, NOAA, Seattle. WA 98112, pers. commun., December 1976. i Figure 1. — This abandoned Japanese-type snow crab pot. recovered 3 mo after close of the commercial fishing season, contained 12 king crab and 14 snow crab. One of each species was dead. EXPERIMENTAL DESIGN While one of our objectives was to learn whether king crab could escape from various styles of pots, we also wanted to estimate the effect of confinement or possible injury during escape on crab viability. Tagged undersize king crab (120-139 mm eye socket to posterior margin of the carapace) and legal-size king crab (150-169 mm long) were placed in pots and returned to the sea floor. Follow- ing a predetermined "soak" (period on the bottom) of up to 16 days, pwts were recovered to identify those crab remaining, including those alive or dead, and new untag- ged king crab that entered the pots during the soak. Tag- ged king crab were also released from the vessel into Chiniak Bay (free-release) to permit observation of any difference in returns between 1) those confined to pots until their escape and 2) crab subjected only to the tag- ging process. Four factors — escape, mortality, new entries, and tag returns — were then compared with length of soak. Since each factor might be influenced by pot design, we selected styles in use by Kodiak area fishermen. Results of preliminary experiments conducted in 1974 prompted us to expand the study during 1975 to include escape £md recovery data from other styles of pots. We also wanted to learn whether presence of bait (chopped herring in bait containers) or dead king crab influenced the entry or escape rate. As a further estimate of effects upon viability caused by confinement, some tagged crab, remaining in study pots that had been soaked for 10-16 days, were released at the surface from recovered pots to observe their recov- ery rate — compared with crab that had escaped during the soak. MATERIALS AND METHODS Many styles of king crab pots are used in the Alaska fishery regularly as well as experimentally by fishermen and researchers. Description of Pots The principal types of commercial crab pots were tested to determine whether size, shape, or tunnel con- figuration might affect crab escapement. Whenever pos- sible, gear and handling techniques were those used in the commercial fishery so that derelict pot conditions would be simulated. Most pots were box-shaped (Fig. 2A). Pot dimensions were 183-213 cm (6-7 ft) square and 76-99 cm (30-39 in) high. Weight varied between about 182 and 318 kg (400 and 700 lb) each, depending upon the size and amount of steel used. Tunnel entrance frames varied from 89 by 19 cm (35 by Vh in) to 102 by 20 cm (40 by 8 in). Several mesh sizes between 10 and 20 cm (4 and 8 in) were used on various pots. The nesting pyramid-shaped pot had a steel-framed base 203 cm (80 in) square with a top frame 122 cm (48 in) square, 61 cm (24 in) above the base (Fig. 2B). The frame was enclosed with 15-cm (6-in) mesh except for the fiberglass top and circular tunnel which provided a 43- cm (17-in) diameter entrance. This style pot is mostly used by small vessels having limited deck storage. Seven of these pots occupy a space 203 cm (80 in) square by 157 cm (62 in) high. Ray Spagnola, master of the MV Tammy hired to fish the study pots, had some custom-made nesting pyramid pots which we designated as "radical pyramid pots" (Fig. 2C). This pot's dimensions were 213 cm (84 in) square at the base with a 122 cm (48 in) upper square frame. Vertical height was 86 cm (34 in) . The tunnel con- sisted of a web-covered steel frame angled 29 cm (11 'A in) down into the pot. Extra framing for a dumping door on one side caused the pots to be unbalanced. Part way through the experiment, counterweights were placed op- posite the door. Small, light-weight nesting conical pots, of the type used by Japanese fishermen for snow crab in the Bering Sea, were recently entered into use in the Kodiak area king crab fishery aboard small boats (Fig. 2D). These conical pots were 152 cm (60 in) in diameter at the base, tapering to 81 cm (32 in) at a height of 69 cm (27 in). A 23-cm (9-in) long tapered plastic collar diminishing from 53 cm (21 in) at the top to 41 cm (16'/4 in) at the orifice served as a tunnel. They were designed to be fished at in- tervals along a groundline, in contrast to heavy king crab pots which are fished individually from a buoyline. Selecting, Handling, and Tagging Crab Two sizes of king crab were selected, smaller than and larger than minimum commercial size of about 145 mm carapace length. Five female crab were included in the 1974 experiments, but the shells of most were too fragile to withstand the handling associated with tagging and return to pots. Consequently, females were excluded dur- ing 1975. Crab for the experiments were captured in pots usually soaked 1-2 days in Chiniak Bay. Fishing depth ranged about 70-164 m (38-90 fathoms). The vessel moved the fishing gear within the central Chiniak Bay area to in- crease catch of crab in the desired size rcmges and to re- main near test pots ab-eady concentrated in one area. Crab were inspected and metisured after removal from fishing pots; rejected crab were immediately returned to the sea. A carapace dart tag was placed through the dor- sal shell on the posterior left side (Powell 1964). Ini- tially, a hole was punched through the shell to accom- modate the nylon tag barb. The barb was then pushed through the shell hole to hold in place a colored plastic disk bearing a serial number and legend. Tagging was rapid, and tagged crab usually remained on deck less than 30 min before the filled test pot was set. Test pots were balanced on the vessel rail, when filled with tagged crab, so they could be pushed over even though heavily weighted. Occasionally a crab was in- jured when one or more of its legs protruded through the meshes and were crushed between the pot frame and 86cm (34in) molded fibergloss top tunnel opening 91cm(36in) by 20 cm (8 m) opprox weight 318kg (7001b) centered 25cm (lOin) from edge \ 56cm(22in)diQ. 43cm (17in)dia. depth of depression 28cm (11 in) 61cm (24in) L opprox. weight 8 2 kg (4001b) l5cm(6in)webon sides-18cm(7in) web on bottom opprox. weight 4 kg (301b) Figure 2. — Dimensions and weights for crab pots used in tlie experiments. 152 cm (60 in) ship's rail. At the time of pot retrieval, dead crab found in the pots were inspected to determine whether such in- juries might have caused their deaths. Unbailed Pot Experiment Escape rates were obtained by allowing pots contain- ing tagged crab to soak for various intervals before retrieval. Tagged crab missing from the pot when it was recovered were presumed to have escaped. Their subse- quent recovery in the commercial fishery was compared with conditions of those released directly into Chiniak Bay. Recovery rates were expected to be similar if no in- jury resulted from confinement or escape effort. Box Shaped Pots During 1975, 60 tagged crab (30 undersize and 30 legal size) were placed in each of 24 "standard" pots (Fig. 2). Groups of three pots were lifted after 1, 2, 3, 4, 7, 10, 15, and 16 days. Six groups of four pots, set in 1974, did not have a prescheduled retrieval date except for the first four pots after 4 days. Since we did not know what escape rate to expect, each pot retrieval day (after the first) was based upon the observed escapement at that time. We anticipated that retrieval for the six groups might take 40 days or more. Instead, they were lifted after 4, 6, 8, 10, 14, and 15 days. Fiberglass Pyramid Pots This test was limited in scope because our objective was simply to determine whether the escape rate was dif- ferent from that of standard pots. Thirty undersize and 30 legal-size tagged crab were placed in each of 12 pots grouped in pairs for 1-, 2-, 3-, 4-, 10-, and 16-day soaks. Radical Pyramid Pots Numbers of crab and soak durations were the same as for the fiberglass pyramid pots. Two tagged crab were observed floating out of the large top opening in these pots just after the pots were pushed into the water. It is not likely many escaped in this way because the pots were heavier on the door side and tended to descend with one side up preventing crab from floating out the open- ing. After each pot reached the sea floor, tension was taken up on the buoy line to upright the pot. In spite of this maneuver, several radical pots remained on their sides (indicated by stained web and steel), and escape- ment promptly approached 100' c as crab could walk free- ly out the misplaced opening. Such "invalid" pots were deleted from the experiment. Conical Snow Crab Pots The Japanese-type pot was considerably smaller than the other pots. Consequently, only 15 undersize and 15 legal-size tagged crab were placed in each one (three groups of four pots were attached to groundlines at 18-m (10-fathom) intervals with single buoylines to the sur- face). As with the standard pots used in 1974, only the first group lift was scheduled after a 4-day soak. The ini- tial escapement was of such magnitude that the remain- ing groups were lifted after 8-10 days on the bottom. Crowding Experiment Occasionally, pots are retrieved that tire completely filled with crab. It is difficult to imagine how 200 or more adult crab could enter a pot or, once inside, effectively escape. The effect of crowding upon escape was tested in two groups of three standard box-shaped pots by placing 75 undersize and 75 legal-size tagged crab in each. A few more than the 150 crab could have been accommodated in the pots, but with more than that number some indi- viduals could have fallen out through the tunnel during the setting process. Baited Pot Experiment Our objective was to determine whether bait (chopped herring or dead king crab) would motivate tagged crab to remain in pots longer than they would have otherwise, thereby causing increased mortality. Bait is either in the derelict ijots at the time of their loss or is formed when- ever animals die in the pots. Although it is an accepted fact that crabs are attracted to bait consisting of fish pieces, we did not know if king crab in baited pots would remain longer than those in unbaited pots or if dead king crab attract living crabs. Research conducted by Han- cock (1974) with Australian lobsters gave indications that dead members of that species repel their living counterparts. Standard baited pots were treated in a manner simi- lar to that in experiments with unbaited pots. In one test, chopped pieces of Pacific herring, Clupea harengus pal- lasi, were placed in 1-qt plastic containers that had per- forations to allow dispersion of solutes. These commer- cial style containers were hung in each of six pots with 60 tagged crab and set near other test pots. Soak periods were 1, 3, and 7 days. A second group of six standard pots were each filled with 60 tagged crab along with 15 freshly killed crab of assorted sizes. New crab entering these pots and those entering unbaited pots were recorded as were those tagged crab which remained — to provide an esti- mate of movement into and out of the pot groups. Confined Crab Viability Experiment Duration of confinement in pots was tested in two ways to learn if duration caused mortality or otherwise af- fected crab survival, even though the crab left the pots before death. First, crab mortalities that occurred dur- ing the various soak periods were tabulated and com- pared. Secondly, returns of tags from the commercial fishery for free-release crab served as controls and were compared with recoveries of crab that had escaped from the various test ptots. A significant difference in recovery rates was accepted as reflecting causes associated with the confinement or escape effort. If recovery were reduced for crab escaping the pots, then we would want to know if it were related to length of confinement. Our experimental procedure did not permit us to record exactly when a particular crab left a study pot. We were, however, able to obtain samples of crab that reflected short (1-4 days) and long (10-16 days) con- finements. Crab that had escaped from pots soaked only 1-4 days were recorded. Because the crab that left the pots after 10 days could not be recorded, we recorded tagged live crab remaining in long-soak pots at the time of their retrieval. Those crab that were apparently uninjured and viable were released, with the tag intact, in a manner similar to the free-released crab. Tag returns from the two groups were compared to determine whether those in the 10- to 16-day group had returns similar to those held 1-4 days. We recognize certain limitations to this procedure, particularly the fact that those crab designated as "long soak" were subjected to one additional lift and further on-deck handling. Moreover, we could not assess the pos- sible predation occurring during any of the short-time periods that surface-released crab were returning to the sea floor. However, no marine mammals were in the vicinity. Incidental Catch Observations Other animals captured in king crab pots may also suffer the consequences of long confinement. Both inver- tebrates and fishes were captured during our studies. No attempt was made to establish escape rates for snow crab, although they were in newly every pot lifted. Because snow crab are considerably smaller than king crab and scuba observations show them to be more ac- tive, it is likely that snow crab can readily escape king crab pots. They may not, however, easily escape from snow crab pots. Records were kept of our capture of fishes. Fishermen were interviewed to learn how frequently nontarget species were captured in pots. Table 1. — Escapement and soak time of undersize and legal-size king crab for various pot types. Crab size and no. Standard pots (1974-75) Radical pyramid pots No. of Avg. ' c' pots escaping Fiberglass pyramid pots No. of Avg. '^"c pots escaping Snow crab conical pots No. of Avg. 'i pots escaping Baited standard pots Standard pots with dead crabs Standard pots crowded of days soaked No. of pots Avg. ''i escaping No. of pots Avg. ^c escaping No. of pots Avg. '} escaping No. of Avg. ^ pots escaping Undersize (120-139 1 3 2 3 3 2 4 5 mm) 31.1 51.6 65.9 64.3 2 2 1 2 73.3 40.4 73.1 27.1 2 2 2 2 11.9 17.2 22.3 37.5 4 26.7 2 I 40.8 82.1 2 2 47.4 76.3 - - 6 4 78.2 _ _ _ _ _ 7 8 9 10 11 12 13 14 Ij 16 3 4 76.6 85.0 — 3 24.7 2 91.2 2 76.8 3 96.4 3 96.5 6 83.0 — — 2 34.3 4 55.8 - — — — 4 6 3 87.0 91.5 87.2 2 80.2 2 43.4 — — — — — — — — 43 9 12 11 5 6 6 Legal (150-169 mm! 1 3 2 3 3 2 4 5 5 - 1 26.4 37.8 37.0 41.3 2 2 1 2 71.7 47.4 65.5 55.2 2 2 2 2 23.2 56.4 51.2 50.4 4 46.3 2 1 21.6 89.3 2 2 28.4 51.4 - - 6 7 8 9 10 11 12 13 14 15 16 4 3 4 51.8 53.1 71.3 - - - 3 49.1 2 68.5 2 55.5 3 84.6 3 85.7 6 69.4 - — 2 41.0 4 71.2 — — — — 4 6 3 67.7 75.4 69.0 - - - - — - — — — — - - 2 67.2 2 54.2 — 43 9 12 11 5 6 6 RESULTS Escape From Standard Pots Percentages of escapement of undersize and legal-size crab from the pots of veirious designs and configurations are shown in Table 1. Percentage escapement of legal and undersize crab from individual standard pots during various times up to 16 days is revealed in the combined data for 1974 and 1975 (Tables 2, 3). To describe the cumulative percent- age escapement with time, the data were first trans- formed to arcsine values and an average computed for each duration of soaking time. Using the asymptotic Table 2. -Escapement of legal-size king crab from standard pots (data from 1974 and 1975 combined). Table 3.— Escapement of undersize king crab from standard pots (data from 1974 and 1975 experiments combined). Number Percent Arcsine Average of days escapement percent Average percent soaked per pot escapement arcsine escapement ' 10 14 15 16 3.33 10.47 62.07 52.00 13.79 21.81 20.00 26.56 10.00 18.44 83.33 65.88 46.43 42.94 27.59 31.69 33.33 35.24 26.67 31.11 48.28 44.03 48.28 44.03 50.00 45.00 43.33 41.15 37.04 37.47 76.92 61.27 50.00 45.00 53.85 47.21 65.38 53.97 40.00 39.23 76.67 61.14 48.28 44.03 62.50 52.24 96.67 79.53 100.00 90.00 96.67 79.53 60.71 51.18 96.67 79.53 20.69 27.06 41.38 40.05 66.67 54.76 55.56 48.22 58.62 49.95 90.00 71.56 LOO.OO 90.00 82.76 65.50 57.69 49.43 100.00 90.00 48.15 43.97 64.00 53.13 82.14 64.97 67.86 55.49 57.14 49.08 28.09 36.96 37.32 39.88 46.22 46.80 59.24 61.22 56.12 65.34 56.51 22.2 36.2 36.8 41.1 52.1 53.1 73.8 76.8 68.9 82.6 69.5 Number Percent Arcsine Average ot days escapement percent Average percent soaked per pot escapement arcsine escapement' 10 14 15 16 10.34 18.72 62.07 52.00 20.83 27.13 50.00 45.00 33.37 35.24 71.43 57.67 70.34 57.04 61.54 51.65 71.43 57.67 66.67 54.76 53.57 47.06 69.23 56.29 60.71 51.18 85.71 67.78 48.15 43.97 96.67 79.53 82.14 64.97 77.78 61.89 75.00 60.00 76.92 61.27 96.67 79.53 70.00 56.79 73.33 58.89 100.00 90.00 100.00 90.00 100.00 90.00 75.86 60.60 96.55 79.37 40.74 39.64 84.62 66.89 92.86 74.55 68.97 56.17 86.21 68.19 100.00 90.00 100.00 90.00 93.10 74.77 82.76 65.50 100.00 90.00 89.66 71.28 83.33 65.88 96.67 79.53 83.33 65.88 81.48 64.52 32.62 45.97 54.34 53.39 64.06 61.05 71.30 71.08 72.23 76.24 69.98 29.1 51.7 66.0 64.4 80.9 76.6 89.7 89.5 90.7 94.4 88.3 'Average arcsine retransformed to percentage escapement. 'Average arcsine retransformed to percentage escapement. regression technique described by Stevens (1951), a curve of the form y = A + BR ' was fitted* to the data. In this model, y is the average arcsine and x is the duration of time in days. The asymptote (A) of the curve, when re- transformed to the original scale, is the estimated value to which the cumulative percentage escapement tends. Estimated values (in the arcsine scale) of the param- eters follow: Parameters Size B Standard deviation of A Legal-size crab (120-139 mm) -42.098 0.8421 63.715 5.451 Undersize crab (150-169 mm) -51.711 0.7604 73.758 2.278 mated value was 92.2%, with lower and upper confl- dence limits of 87.4% and 95.9%. Effect of Bait or Dead Crab Bait in the form of chopped herring or dead crab did not "hold" tagged king crab in the test pots. Crab left baited pots more rapidly than unbaited pots (Fig. 4). The occurrence of new untagged king crab at time of retrieval in the test pwts baited with herring was many times greater than pots containing dead crab or no bait (Fig. 5). After 7 days, the new entries in herring-baited pots ap- proached the rates for the unbaited and dead-crab- baited pots, indicating that the herring became less effective as bait with time. Dead crab in test pots did not attract live king crab to the pots. Using these values and retransforming to the original scale, we estimated the cumulative percentage escape- ment with time (Fig. 3). Also shown in Figure 3 are observed data points and a 95% confidence interval for the asymptote. For legal-size crab, the estimated asymp- tote was 80.4% with lower and upper 95% confidence limits of 63.5% and 93.0%. For undersize crab the esti- ^The asymptotic regression analysis was completed using a computer program written by George Hirschhom of the Northwest and Alaska Fish- eries Center, National Marine Fisheries Service, NOAA, Seattle, WA 98112. Mortality in Pots Crab remains found in each pot were examined for tag numbers or scars. No unmarked crab were found dead. It is imlikeiy that any dead crab were unaccounted for as the carapaces remained intact even during a 15-day soak, and the pxit mesh-size was small enough to prevent shells from falling out during the lift. Mortality did not in- crease with time of soak (Table 4). However, the 15-day soak was a relatively short period to observe mortality caused by confinement. Natural mortality, tagging in- jury, and handling probably all contributed to the LEGAL CBABS Figure 3. — Average escapement retransformed to percent for small and large king crab from standard pots (data from 1974 and 1975). e e 10 12 DAYS SOAKED e 8 10 12 DAYS SOAKED Figure 4. — King crab escapement f^om baited and unbaited pots after various soak Intervals. DAYS SOAKED DAYS SOAKED observed mortality. As noted above, injuries did occur when crab-laden pots were pushed across the ship's rail and over the side. Some legs protruding through bottom meshes were damaged, particularly in the experiment where 150 crab were crowded in each pot. We believe this may have contributed to the mortality observed for both leged-size and undersize crab in that experiment. How- ever, mortalities occurred to both injured and appar- ently uninjured crab. Tag Returns Returns of tagged crab escaping pots were greater in 1975 (30.0%) than during 1974 (16.0%) even though fish- ing effort was somewhat less in 1975 (Tables 5, 6). More- over, we used a two-color, highly visible tag during 1975, which was more likely to attract attention of fishermen or processors than the single-color (dull orange) tag used in 1974. Recovery of escaped undersize tagged crab was less in all experiments them for legal-size crab. However, there is no evidence that higher tagging loss caused this. On several occasions, fishermen reported seeing a tag on an undersize crab as it was being released into the water but too late to retrieve it. Small crab taken upside down from pots by commercial fishermen were not turned over before release. Thus carapace tags may have been over- looked. Six of the 10 vessels returning most of the 1975 tags were among the top 10 vessels returning tags in 1974. These vessel crews were especially alert to the presence of tags on both undersize and legal -size crab. Viability of Escaped Crab K confinement in pots contributed to crab mortality, either in the p)ots or after escapement, we would expect mortality to be positively correlated with length of soak. No such correlation was observed to the end of confine- ment, but subsequent recovery of tagged crab indicated one correlation. The viability of crab that escaped the pots was tested by comparing recoveries of tagged crab from various experiments using pots with those free- released. The latter crab were promptly tagged and Figure 5. — Entry of new king crab (large and small combined) into pots containing herring, dead crab, or no bait. released except for the initial group in 1974, which was held for under 2 days in the live tank. All were released in the area where experimental pots were soaking. As a result, free-release crab were distributed at intervals throughout the escape period of crab emerging from soaking pots. Statistical tests, based upon the "G" statistic (Sokal and Rohlf 1969), showed no significant difference (30% level) in percentage recovered among 1975 free-releases and 1-4 day confinement for both undersize and legal- size crab. However, jjercentage recovered for both under- size (2 returned from 86 released) and legal-size (21 returned from 120 released) crab, 2.3% and 17.5%, respectively, confined for 10-16 days was significantly (P <0.05) smaller than for the free-release groups (34.9% undersize and 35.2% legal size) and those confined for 1-4 days (31.4% and 33.1%). Furthermore, the recovery percentage for undersize crab confined 10-16 days was significantly less {P <0.05) than that for legal-size crab confined for the same length of time. Only 1975 data were compared in this analysis to reduce effect of less visible tags used during 1974. Incidental Catches Those commercial fishermen interviewed agreed that the occurrence of other fish and invertebrate species in crab pots varied widely by fishing location and time of year. At times, fishermen using small-mesh web on their pots captured one or more Pacific cod in each pot lifted; Pacific halibut were taken less often. However, the fishermen reported that under some conditions halibut were present in up to 9% of their commercial pots lifted. All fish, except for viable halibut, were used for crab bait. We captured both Pacific halibut and Pacific cod in Chiniak Bay. The remains of eight halibut, ranging in length from 84 cm to 123 cm, and six cod, from about 60 cm to 70 cm, were taken from 121 lifts during 1975. Soak time averaged 2 days. Occurrence was 6.6% for halibut and 5.0% for cod. All cod were viable, whereas only one halibut was alive. Six halibut were captured during the 1974 tests. Fishing effort, although not recorded, was considerably less than in 1975. Table 4. — Observed mortality in pots at retrieval for tagged king crab conrined in pots of various designs or configurations; except where noted, pots were unbaited. Days Undersize Legal size Pot style No. No. found %o( No. No. found %of tested soak tagged dead tagged tagged dead tagged Standard 4 88 2 2.3 90 1 1.1 (1974) 6 117 4 3.4 119 10 8.4 8 120 0 0.0 119 6 5.0 10 120 3 2.5 120 3 2.5 14 120 4 3.3 119 3 2.5 15 120 3 2.5 120 6 5^ 685 16 2.3 687 29 4.2 Standard 1 85 3 3.5 90 2 2.2 (1975) 2 90 9 10.0 90 5 5.6 3 60 7 11.7 60 3 5.0 4 60 6 10.0 60 1 1.7 7 90 9 10.0 90 13 14.4 10 90 8 8.9 90 4 4.4 15 77 2 2.6 88 11 12.5 16 90 _3 3.3 89 _5 5.6 642 47 7.3 657 44 6.7 Standard 7 225 23 10.2 225 21 9.3 (crowded) 9 225 21 9.3 225 24 10.7 450 44 9.8 450 45 10.0 Standard 1 60 1 1.7 60 0 0.0 (with bait) 3 30 2 6.7 30 2 6.7 7 60 ^ 6.7 _59 _5 8.5 150 7 4.7 149 7 4.7 Nesting 4 60 2 3.3 60 2 3.3 snow crab 8 45 3 6.7 45 5 11.1 10 60 _4 6.7 60 _5 8.3 165 9 5.4 165 12 7.3 Nesting 1 60 2 3.3 60 4 6.7 fiberglass 2 60 2 3.3 60 14 23.3 pyramid 3 60 10 16.7 60 11 18.3 4 60 1 1.7 60 8 13.3 10 59 9 15.3 60 6 10.0 16 _60 0 0.0 60 J_ _L7 359 24 6.7 360 44 12.2 Nesting 1 60 0 0.0 60 0 0.0 radical 2 56 2 3.6 60 1 1.7 pyramid 3 30 4 13.3 30 1 3.3 4 60 1 1.7 60 2 3.3 10 invalid 16 60 J^ 6.7 60 7 11.7 266 11 4.1 270 11 4.1 Standard 1 60 3 5.0 60 3 5.0 (with planted 4 60 1 1.7 60 2 3.3 dead crab) 7 60 _9 15.0 _60 J^ 6.7 180 13 7.2 180 9 5.0 SUMMARY AND CONCLUSIONS Analysis of the data indicates that an average of 92% of large undersize king crab and 80% of small legal-size king crab would escape from standard pots. Interpreted con- versely, these data indicate retention of an average of 8% of undersize and 20% of legal-size crab. With respect to crab confined in pots, experiments show that the presence of herring bait or dead crab did not reduce the escape of crab from the pots. Crab that es- caped after 1-4 days were shown by tag recoveries not to have suffered additional postescape mortality as a result of short-term confinement. On the other hand, 10-16 day confmement resulted in reduced recovery. Any procedure which would permit rapid escape of king crab from the pots would, therefore, introduce healthier viable crab back into the commercial stocks. Although we did not make a detailed analysis of cap- ture of species other than king crab, commercially useful fishes were found in the pots. These included the valuable Pacific halibut. We must emphasize that we do not know how memy 10 Table 5. -Combined return of tags from undersize and legal-size king crab that escaped from each 1974 experiment during various soak intervals. Standard pot Jammed Free release j«jg Returned nc ibait standard pots No. Returned Snow No. crab pot Days No. Returned Returned soaked released No. '"c escaped No. % escaped No. % escaped No. % 0 694 170 24 4 _ _ — 87 14 16 _ _ _ 43 6 14 6 — — — 145 20 14 _ _ _ — — — 7 — — — — — — 368 57 15 — — — 8 — _ _ 183 35 19 _ _ _ 31 4 13 9 _ _ _ — — — 370 63 17 10 — — — 213 37 17 _ _ _ 70 20 29 U _ _ _ 180 21 12 15 — — — 208 27 13 — — — — — — Total 1,016 154 15.2 738 120 16.3 144 30 20.8 Table 6.— Combined return of tags from undersize and legal-size king crab that escaped from each 1975 experi- ment during various soak intervals. Standard pots Pyramid pots Free release No bait Herring baited pot Baited pot (dead crab) Radical design Typical design Days soaked !Z 3 Z P z o *- Z « Z 3 0 365 128 35— — — — — — — — — ______ 1 _ _ _ 49 12 24 37 11 30 43 11 26 87 35 40 20 12 60 2 _ _ _ 75 25 33 _ _ _ — — — 50 20 40 36 7 19 3 ___ 56 14 25 48 16 33 — — — 38 16 42 36 9 25 4 _ _ _ 64 15 23 _ _ — 75 26 35 48 18 38 48 14 29 7 _ _ _ 103 30 29 88 34 39 70 20 29 — — ——— — 10 _ _ _ 67 20 30 _ _ _ — _ _ _ _ _ 39 10 26 15 ___57 22 39— — — — — — ______ 16 _ _ _ ^ _28_ 21 ^ — _-^ --_ — _-^ _80 _23 _29 _58 ^1 ?f Total 605 166 173 61 188 57 303 112 237 66 Average 27.4 35.3 30.3 37.0 27.8 king crab enter derelict jwts and, until this is deter- mined, the impact of lost pwts upon the Alaska king crab population is uncertain. ACKNOWLEDGMENTS Guy Powell, and Rod Kaiser, Alaska Department of Fish and Game, Kodiak, were instrumental in the suc- cess of these experiments by reviewing experimental plans. Powell supervised the recovery of our crab tags. Ray Spagnola, master of the chartered crab vessel Tam- my, and his crew contributed substantially to the field operations. Robert Loghry and Craig Forrest, Biological Technicians with the National Marine Fisheries Service, Auke Bay, Alaska, participated in all of the field studies. Rene Cerda, visiting scientist from the University of Valparaiso, Chile, participated during 1975. LITERATURE CITED HANCOCK, D. A. 1974. Attraction and avoidance in marine invertebrates — their possible role in developing an artificial bait. J. Cons. 35:328-331. HIPKINS, F. W. 1974. A trapping system for harvesting sablefish. U.S. Dep. Com- mer., NOAA, Natl. Mar. Fish. Serv., Fish. FacU-7, 20 p. POWELL. G. C. 1964. Fishing mortality and movements of adult male king crabs, Paralithodes camtschatica (Tilesius), released seaward from Kodiak Island. Alaska. Trans. Am. Fish. Soc. 93:295-300. REARDEN, J. 1976. Alaska's king crab fishery. Alaska 42(3):4-6, 71-72, 74-76. SOKAL, R. R., and F. J. Rohlf 1969. Biometry. W. H. Freeman and Co., San Francisco, Calif., 776 p. STEVENS, W. L. 1951. Asymptotic regression. Biometrics 7:247-267. 11 672. Seasonal occurrence of young Guld menhaden and other fishes in a northwestern Florida estuary. By Marlin E. Tagatz and E. Peter H, Williins. August 1973, iii + 14 p., 1 fig.. 4 tables. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington. D.C. 20402. 67.T. Abundance and distribution of inshore henthic fauna off southwestern Long Island. N.Y. By Frank W. .Steimle. Jr. and Richard B. Stone. December 1973. iii + 50 p.. 2 figs.. .5 app. tables 674. Lake Erie bottom trawl explorations. 1962-66. By Edgar W. Bow- man, January 1974. iv + 21 p.. 9 figs., 1 table. 7 app. tables. 675. Proceedings of the International Billfish Symposium. Kailua- Kona. Hawaii. 9-12 August 1972. Part 1. Report of the Symposium. March 1975. iii + 33 p.; Part 2. Review and contributed papers. July 1974. iv + 3.55 p. (.38 papers); Part 3. Species synopses. June 1975, iii + 159 p. (8 papers). Richard .S. Shomura and Francis Williams (editors). For sale by the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 676. Price spreads and cost analyses for finfish and shellfish products at different marketing levels. By Erwin S. Penn. March 1974. vi -f 74 p., 15 figs.. 12 tables. 12 app. figs.. 14 app. tables. For sale by the Superinten- dent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 677. Abundance of benthic macroinvertebrates in natural and altered estuarine areas. By Gill Gilmore and Lee Trent. April 1974. iii -t- 13 p.. 11 figs.. 3 tables. 2 app. tables. For sale by the Superintendent of Documents. U.S. Government Printing Office, Washington, D.C. 20402. 678. Distribution, abundance, and growth of juvenile sockeye salmon. Oncorhynchus nerka, and associated species in the Naknek River system, 1961-64. By Robert J, Ellis. September 1974. v -)- 53 p.. 27 ligs., 26 tables. For sale bv the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 679. Kinds and abundance of zooplankton collected by the I'SCG icebreaker Glacier in the eastern Chukchi Sea. September-October 1970. By Bruce L. Wing. August 1974. iv -\- 18 p.. 14 figs.. 6 tables. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. DC. 20402. 680. Pelagic amphipod crustaceans from the southeastern Bering Sea. June 1971. By Gerald A. Sanger. July 1974. iii -I- 8 p.. 3 figs., 3 tables. For sale by the Superintendent of Documents. U..S. Government Printing Of- fice. Washington. DC. 20402. 681. Physiological response of the cunner. Tauto^olabrus adspersus, to cadmium. October 1974. iv -f 33 p.. 6 papers, various authors. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. DC. 20402. 682. Heat exchange between ocean and atmosphere in the eastern North Pacific for 1961-71. By N. E. Clark, L. Eber, R. M. Laurs. J. A. Rcnner. and J. F. T. Saur. December 1974, iii -I- 108 p.. 2 figs.. 1 table. 5 plates. 683. Biocconomic relationships for the Maine lobster fishery with con- sideration of alternative management schemes. By Robert L. Dow. Frederick W. Bell, and Donald M. Harriman. March 1975, v -I- 44 p.. 20 figs.. 25 tables. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington, DC. 20402. 684. Age and size composition of the Atlantic menhaden. Brevoortia tyrannus, purse seine catch. 1963-71. with a brief discussion of the fishery. By William R. Nicholson. June 1975. iv + 28 p., 1 fig.. 12 tables. 18 app. tables. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington, D.C. 20402. by the Superintendent of Documents. U.S. Government Printing Office, VVashington, D.C. 20402. 686. Pink salmon. Oncftrhunchus gorbuscha, tagging experiments in southeastern Alaska, 19,38-42 and 1945. By Roy E. Nakatani. Gerald J. Paulik. and Richard Van Cleve. April 1975. iv -f 39 p.. 24 figs.. 16 tables For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. D.C, 20402. f>87. Annotated bibliography on the biology of the menhadens. Gentjs Brcvdiirtiit. 1963-1973. By John W. Reintjes and Peggy M. Keney. April 1975, 92 p. For sale by the Superintendent of Documents, U.S Government Printing Office. Washington, D.C. 20402. 688. Effect of gas supersaturated Columbia River water on the survival of juvenile chmtxtk and coho salmon. By Theodore H. Blahm. Robert J. McConnell, and George R. Snyder. April 1975. iii -)- 22 p.. 8 figs., 5 tables. 4 app. tables. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington, D.C. 20402. 689. Ocean distribution of stocks of Pacific salmon. Oncorhynchus spp., and steelbead trout. Salma ^ai'-dneril, as shown by tagging experiments. Charts of tag recoveries by Canada. Japan, and the United States. 19.56- 69. By Robert R. French. Richard G. Bakkala, and Doyle F. Suther- land. June 1975. viii -f 89 p.. 117 figs.. 2 tables. For sale by the Superintendent of Documents. U.S. Government Printing Office, Washington, D.C. 20402. 690. Migratory routes of adult sockeye salmon, Oncorhynchus nerka, in the eastern Bering Sea and Bristol Bay. By Richard R. Straty. April 1975. iv + 32 p.. 22 figs.. 3 tables. 3 app. tables. For sale by the Superintendent of Documents. U.S. Government Printing Office, Washington. D.C. 20402. 691. .Seasonal distributions of larval flatfishes (Pleuronectiformes) on the continental shelf between Cape Cod. Massachusetts, and Cape Lookout. North Carolina. 1965-66. By W. G. Smith. J. D. Sibunka. and A. Wells. June 1975. iv -h 68 p., 72 figs., 16 tables. 692. Expendable bathythermograph observations from the NMF.S/MARAD Ship of Opportunity Program for 1972. By Steven K. Cook. June 1975. iv + 81 p.. 81 figs. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. DC. 20402. 693. Daily and weekly upwelling indices, west coast of North America, 1967-73. By Andrew Bakun. August 1975. iii + 114 p., 3 figs., 6 tables. 694. Semidosed seawater system with automatic salinity, temperature and turbidity control. By Sid Korn. .September 1975, iii + 5 p., 7 figs., 1 table 695. Distribution, relative abundance, and movement of skipjack tuna, Katsutronus pelamis. in the Pacific Ocean based on Japanese tuna long- line catches. 1964-67. By Walter M. Matsumoto. October 1975. iii + ,30 p., 15 figs., 4 tables. 696. Large-scale air-sea interactions at ocean weather station V, 1951- 71. By David M. Husby and Gunter R. Seckel. November 1975, iv + 44 p., 11 figs.. 4 tables For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. DC. 20402. 697 Fish and hydrographic collections made by the research vessels Dolphin and Delaware II during 1968-72 from New York to Florida. By S. J. Wilk and M. J Silverman. January 1976. iii + 159 p.. 1 table. 2 app. tables. For sale by the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C. 20402. 698. Summer benthic fish fauna of Sandy Hook Bay. New Jersey. By Stuart J. Wilk and Myron J. Silverman. January 1976. iv + 16 p., 21 figs.. 1 table. 2 app. tables. For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. DC. 20402. 685. An annotated list of larval and juvenile fishes captured with sur- face-towed meter net in the South Atlantic Bight during four RV Dolphin crui.ses between May 1967 and February 1968. By Michael P. Fahay. March 1975, iv + 39 p., 19 figs., 9 tables, 1 app. table For sale MBL WHOI Lpbrarv 699. Seasonal surface currents off the coasts of Vancouver Island and Washington as shown by drift bottle experiments. 1964-65. By W. James Ingraham. Jr. and James R. Hastings. May 1976, iii -t- 9 p., 4 figs., 4 tables 5 WH SE 045- UNITED STATES DEPARTMENT OF COMMERCE *J*TlONAl OCEANIC AND AIMOSPMERiC ACMINISTRATION NAtlONAl MARINE FISHERIES SERVICE SCIENTIFIC PUBLICATIONS STAFF ROOM 450 I 107 N E 45TM ST SEAIIIE, WA 98105 OFFICIAL tUSINESS POSTAGE AND FEES PAID Li S DEPARTMENT QF COMMERCE COM 210 THIRD CLASS BULK RATE OIUiICiON ,l)|.li"l'. Ob' FISH & WM.Dli MAKIMI'l ii(;iMiK;i'i Jiitrvi'; NI'A'JI'Oli'l , oil ')Y )6'; NOAA SCIENTIFIC AND TECHNICAL PUBLICATIONS NOAA. the National Oceanic and Atmospheric Administration, was established as part of the Department of CoTTimcrce on October 3. 1 970. 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