ARMETTA and STEVENS: BIOLOGY OF THE HAIR CRAB 



growth rate for carapace length ( Yamamoto 1971) 

 and females of 50 mm RL (45 mm CD an 8-17% 

 growth rate (Sakurai et al. 1972). 



Molting periods for adult hair crab vary with 

 sex and locality. In general, males distributed 

 along the coasts of Hokkaido and Korea molt be- 

 tween the months of January and July (Yoshida 

 1940; Demon et al. 1956; Matui 1970; Sakurai et 

 al. 1972 > and females molt during the periods of 

 April to June (Yamamoto 1966) or August to 

 February (Sakurai et al. 1972). 



Amphipods, anomurans, and isopods are impor- 

 tant food items of the hair crab and peak feeding 

 occurs at midday (Hirano 1935; Sakurai et al. 

 1972; Abe 1973). Hair crab are prey to fish species 

 including various cottids (Sakurai et al. 1972; 

 Abe 1973, 1982), salmon (Takeuchi 1972), and cod 

 (June*'), and are occasionally eaten by red king 

 crab, Paralithodes camtschatica , (Cunningham 

 1969). 



Hair crab migrate between shallow and deeper 

 waters for mating purposes or in response to tem- 

 perature changes (Yamamoto 1966; Sakurai et al. 

 1972). Primiparous females mate nearshore dur- 

 ing winter, whereas multiparous females mate in 

 deeper waters during autumn. Juveniles remain 

 nearshore in water temperatures up to 15°C in 

 late summer but adults move offshore. Hair crab 

 also migrate along shore possibly to avoid in- 

 creased densities (Hirano 1935; Abe 1977). 

 Hirano reported that the longest straight-line mi- 

 gration of a tagged crab was 18 km over a 16-d 

 period and the greatest migration speed was 1.39 

 km day; however, the remaining 180 crabs recov- 

 ered (442 tagged crabs released) within a 48-d 

 period were at the site of release or within 7 km. 



Hair crab have been fished in Japanese and 

 Korean waters with the use of conical pots (Fig. 

 4), trawls, and gill nets (Matui 1970; Yamaha 

 Fishery Journal 1981). In any month of the year 

 fishing occurs at some location around Hokkaido; 

 it occurs from about November to April offshore of 

 southern Hokkaido (Kawakami 1934; Yamaha 

 Fishery Journal 1981) and from March to Decem- 

 ber offshore of northern Hokkaido (Kawakami 

 1934; Matui 1970; Tanikawa 1971). Management 

 measures have included area closures, total catch 

 limits, pot limits, legal-size restrictions, and 

 male-only restrictions (Matui 1970; Yamaha 

 Fishery Journal 1981). Hirano (1935) and 

 Kawakami (1934) believed that hair crab are es- 

 pecially vulnerable to fishing pressures owing to 

 "localized" migratory behavior, low number and 

 fecundity of females, and the extended breeding 

 period. By 1980, about 10 t of hair crab were har- 

 vested offshore of Hokkaido every day, with 909^ 

 of the harvest transported live to fish markets 

 throughout Japan (Iversen^), and the remaining 

 10% sold frozen. 



U.S. fishermen began to land hair crab from the 

 EBS in 1979 (Table 1). The majority of the com- 

 mercial harvest has occurred incidental to snow 

 (Tanner) crab (Chionoecetes sp.) fishing in the 

 Bering Sea during the months of March through 

 June, however, fishing season is not restricted. 

 Only male crabs are landed. The Pribilof District 

 (see Results for description of district) contributed 

 94-98% of the total Bering Sea catch during 1980- 

 84. Harvested crabs averaged 105.7 mm CL and 

 0.91 kg in 1984. Landings ranged from 2 t in 1979 

 to a peak of 1,108 t in 1981. Modified, baited king 

 and Tanner crab pots are normally used. Pribilof 

 Islanders, however, conducted an experimental 



•y. June, Fisheries Research Biologist, Northwest and Alaska 

 Fisheries Center, National Marine Fisheries Service, NOAA, 

 7600 Sand Point Wav N.E.. Seattle, WA 9811.5, pers. commun. 

 December 1982. 



"R. Iverscn, Regional Fisheries Attache, U.S. Embassy, 

 Tokyo, Japan, APO San Francisco, CA 96503, pers. commun. 

 August 1982. 



Table 1— Statistics of the US. commercial fishery of Erimacrus isenbeckii in the eastern Bering 

 Sea (modified from Griffin and Dunaway, see text footnote 3). Mean length determined from port 

 sampling, mean weight from landing records. 



527 



