ARMETTA and STEVENS: BIOLOGY OF THE HAIR CRAB 



- 64' N 



179" E 



1 



175" W 



169' 



163" 



157- 



Figure 5. — Standard station pattern for NMFS eastern Bering Sea summer surveys, 1979-84. Actual stations occupied may have 



differed slightly from this pattern in any year. 



Program (OCSEAP) cruise to the Pribilof Islands 

 in May 1983. The seasons and durations of cruises 

 are shown in Figure 6. Additional data concern- 

 ing the NMFS summer cruises is contained in 

 Otto et al. (1985, for the 1984 survey; similar 

 documents are produced annually). Eastern otter 

 trawl gear was used on all vessels throughout the 

 6-yr study period, except during the May 1983 

 OCSEAP cruise. On that cruise, either a 3.0 m 

 beam trawl, 7.2 m try-net, or 1.2 m rock dredge 

 were used to collect crabs, depending on bottom 

 type determined from sediment samples taken 

 with a Shipek bottom grab at each station. Fish- 

 ing during both February cruises and the May 

 1983 cruise was conducted round-the-clock, 

 whereas that during the summer surveys oc- 

 curred only during daylight hours. Data collected 

 during the February cruises and May 1983 cruise 



were not used in this report to determine distribu- 

 tion and abundance of hair crab in the EBS be- 

 cause of the limited area surveyed; only 1979-84 

 summer survey data were used for that purpose. 

 Because different techniques were involved and 

 no comparative fishing was conducted, catches of 

 hair crab during the May 1983 cruise cannot be 

 compared statistically with those from the sum- 

 mer surveys. 



Tows were made in a systematic grid pattern 

 with stations located 37 km (20 nmi) apart. Dur- 

 ing several years, extra tows were made in areas 

 of higher hair crab abundance around the Pri- 

 bilofs and in Bristol Bay, which increased the pre- 

 cision of population estimates during those years. 

 Each tow lasted 0.5 hour and most were 2.2-3.3 

 km (1.2-1.8 nmi) long. Bottom temperatures were 

 recorded with an expendable bathythermograph 



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