A Review of Worldwide Fisheries for Lithodid Crabs (Decapoda: Anomura: Lithodidae) and Their Fluctuations
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Bi ology ofAnomura II (A .Asakura ，e d.)，Cr ustaceanR esearc h，Sp ec ialN umber6: 167-185，2006 A review of worldwide fisheries for lithodid crabs (Decapoda: Anomura: Lithodidae) and their fluctuations R obert S. Otto Abstra ct.-Lithodid crab fi sheries began species within these genera，trends in landings before1900 in Japan and spread across the and cu汀 ent status of major stocks contributing North Pacific Ocean by1940. Fisheries targeted to the world lithodid landings. lncidental or red kin gcrab (Paralithodes ca mtsc hati cus) with experimental fisheries for Neolithodes spp. and lesser amounts of blue king crab (P. platypus) for Lopholithodes spp. are omitt ed，because and brown king crab (P. brevip es) .Paralithod es documented landings are sporadic，trends spp.，es pec iall yred kin gcrabs ，h ave always are not evident and magnitudes negligible. dominated lithodid fisherie s. Golden king crab Likewise，1 have excluded recreational or (Lithodes aequispinus) becam eimportant in personal use fisheries，because statistics are North Pacific Ocean waters after major decline s frequently incomplete and known landings are in red king crab fisheries in the early 1980's. Southern kin gcrab (Lithodes sa ntolla) are fished generall ysm a ll relative to commercial白sheries. in so uthern South America along with softshell red crab (Paralomis granulosa). These five species DATASOURCES accounted for more than 89% of lithodid landings for 1984・2003. World lithodid landings pea ked at 1use United Nations Food and Agricultural 150，100 metric tons (t) in 1966 after development Organization (FAO) landing statistic sas a in pre-World War 11 Asia and rapid post-1950 starting point and more detai led publications ex pansion in A laskaand Asia. The world Ii thodid to dissect the FAO series into their component landingsfell to 60，540 tin 1973 but rebounded parts .1 have used the 1950- 2003 FAO to 104，970 tin 1980，due to abundant eastern electronic data set (www.fao.o rg/waicent/ Bering Sea red king crab stocks. Eastern Bering fao info /fi shery /sta ti stlfi so白/fishplus.asp) to Sea and G ulf of Alaska red king crab stocks soon examine post World War 11 trends. collapsed，and landingsfell to alow of 40，920 Two probl ems are pa口ially resolved in this tin 1983. The world Ii thodid landings reached way.First old er FAO statistics mayr efer to 81 ，390 tin 1997 with increasedRu ss ian landings， ， the area where aspecies or group was landed but have declined sharplyto only 32，610 t. In the 1960's ，Russi anscie nti stss uccess full yintroduced as opposed to where it was caught or some red king crabs to the Atlantic Ocean and re sultant combinati on of the two.Second ，m 句or fishing fisheries currently provide 9%of world Ii thodid nations (Japan，Ru ssia ，USA) landinglithodid landings. Elsewhere，Paralithode ss pp. landings crabs from the North Pacific Ocean frequently trend downward，while other lithodid species are reported their landings to FAO as “king crabs" sta bl eor increasi ng. which may have included severals peciesof Paralithodes or even mixtures of Paralithodes and Lithodes. Russian FAO landingstat istics INTRODUCTION (actually USSR combinedwith later Russian Commercialfisheries for lithodid crabs are Federation ，and hereafter termed Russia)have almost entire lymade up from landings of three recentl ybee nimproved andare now given by genera: Parαlithodes，Lithodes and Paralomis. species. The species composition of Japanese This paper reviews the historyof fisheries for king crab (Parαlithodes spp.) catch from the 168 R. S. Otto northeast Pacific Ocean is known from the now- PRINCIPAL SPECIES defunct lnternational North Pacific Fisheries Commission records and that of Russia from In FAO statistics and commercial fisheries various international negotiations (see Otto， literature ，crabs of the genus Paralithodes 1981).1 use these data to prorate the FAO are referred to as king crabs，but members total catch figures for Paralithodesby species of Lithodesor Paralomis are referred to as for the northeastern Pacific area and also by king crabs or stone crabs depending upon the the amounts caught (as opposed to landed) in species. At their outset，almost all worldwide northeastern and northwestern FAO areas. All lithodid landings were taken in tangle nets，but landings are expressed in metric tons (t) tangle nets were largely gone by 1975. Now Similarly，national statistics for king crab virtually all landings are taken with pots or landings in the United States include all species traps. Pots are considered less destructive to of Paralithodes and Lithodes，but for historical untargeted portions ofthe catch such as females reasons are referred to as Paralithodes spp. or juveniles. Other conservation measures Landing data from the Alaska Department of usually include alegal minimum size limit，a Fish and Game (e.g. ，Alaska Department of prohibition against harvesting females，seasonal Fish and Game，2003; Hebert eta l. ，2005) were c10sures ，as we11 as quotas to limit harvest. used to estab1ish the approximate composition Enforcement of conservation measures varies of United States landings. 1considered the widely among fisheries. Despite conservation catch of blue king crab (Paralithodes plaぴ'P us ) measures，almost all of the world's major from the eastem Bering Sea as aproxy for the Paralithodes spp. fisheries are in aserious state total even though small amounts (ca く 50 t) of of decline. b1ue king crabs are taken in parts of the Gu1f of A1aska.1 was able to approximate 1andings of Paralithodes spp. golden king crab (Lithodesaequispinus) in the Heavily exploited members of USA by summing published data，but these do Paralithodesinhabit shallow continental not include landings where less than 3vessels shelf waters that do not exceed 300 m and are were fishing. These omissions are small (ca typically less that 200 m. Cahn (1948) shows く 20 t) and therefore inconsequentia1 at the that red king crab was the preferred ，as well as 1eve1 of aggregation presented here. Pub1ished the dominant，species in Japanese 1andings as Alaskan crab fishery data are given by seasons the first commercial king crab fisheries were that sometimes span January 1and while developed，and throughout the pre- World War using these to adjust calendar year national 11 era (Fig. 1) .This was also true of developing landings results in some errors ，there is abetter Russian fisheries. Red king crabs continued to reckoning oftrends by species or group. dominate Asian king crab fisheries throughout 1do not have away of estimating species the post-war period (Fig. 2A) and dominated composition for Japanese landings from developing North American fisheries in Alaska the northwestern Pacific Area and have not as well (Fig. 28). The successful introduction attempted to dissect them beyond segregating of red king crabs to the 8arents Sea (Kuzmin Hokkaido red king crab (Paralithodes et al. ，1996) and its subsequent spread into camtschaticus) landings from the remainde r. Norwegian waters has resulted in asignificant A detailed account of North Pacific crab fishery. Red king crabs dominate landings of fisheries，including Lithodidae，is contained Paralithodesspp .(Fig. 3A) as well as world in Otto & Jamieson (2003)，while asynopsis landings.Correcting FAO statistics for the of the biology of the Lithodidae is given by composition of catch for Russia，Japan and Zaklin (2002). Here 1consider m 句or trends in USA in the northeastern Pacific ，red king wor1 dfisheries for lithodid crabs and omit most crabs account for 84.8 % of Paralithodes spp. biological detai l. landings and 73.9% of world lithodid landings Worldwide fis heries for li thodid crabs 169 40.00 35.00 的 30.00 dm『 g υ 25.00 h h O 20.00 ω z o 15.00 コJ - E 10.00 5.00 0.00 1902 1907 1912 1917 1922 1927 1932 1937 1942 YEAR 口HOKKAIDO& S.KURILES 固 N.KURILES & KAMCHATKA .KARAFUTO 園 F L OATERS Fi g. 1.Landin gs of crabs (Paralithodes spp.) used in the Japanesecanned crab industry prior to World War 1 1. Red kin gcrab (Paralithodes camtsc hati cus)was the dominant species . summed over the years 1984-2003. they can not be depicted in Fig.3A. The blue king crab is acold-adapted species Two deep water species of Paralithodes that is very similar to the red king crab in occur off California but have rare ly been appearance and general ecological relationsh ips ， the object of fisheries .Reported landings of but populations tend to be small and localized . Parαlithodes spp. from the southerηhemisphere Blue king crabs contribute significantly to are in error，but of inconsequential magnitude. landings from North Pacific Ocean (NPO) waters，particularly in the eastern Bering Sea Lithodes spp. (particularl yPribilof Is lands and St. Matthew Species of the genus Li thodes are found Islands) ，the Sea of Okhotsk as we ll as off the in temperate waters throughout the world， Russian Koryak coast near Cape Olyutorskiy and there are many more species of Lithodes and Cape Navarin. Blue king crabs became than Paralithodes，that is confined to the relatively important in later years as red king North Pacific. Dawson (1989) lists 17 species crab stocks declined and sometimes dominated within Li thodes as compared to five species eastem BeringSea king crab catches. of P aralithodes. Most Li thodes are found in Brown king crab (P. brevipes) were also deep，outer continental shelfwaters ，occur at utilized in the pre- World War Il era (Cahn， low population densities or simply lack the 1948)，and became important in post-war meat content to attract commercial fisheries. Japanese landings from Hokkaido (Abe，1992). There have been experimental or incidental Brown king crabs became the largest king crab landings of several species，and these make up fishery in Hokkaido waters after the virtual part of the landings reportedas Li th odes spp.