FISHERY BULLETIN: VOL. 72, NO. 3 



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Figure 7. — Distribution and relative abundance of king crab larvae sampled at stations in the southeastern Bering 



Sea, 16 July-21 September 1969 and 1970. 



DISTRIBUTION AND RELATIVE 

 ABUNDANCE 



Although sampling locations and dates were 

 different each year, I determined that I could 

 combine the data for both years for consideration 

 of distribution and abundance. For each semi- 

 monthly period, I tabulated the degree squares 

 (the areas bordered by 1° of latitude and longi- 

 tude) that were sampled in both years. This re- 

 sulted in 14 degree squares, 7 each for the latter 

 half of May and June. For each of the two semi- 

 monthly periods, the median catch per tow was 

 computed and the degree squares were ranked 

 "good" or "poor" on the basis of whether their 

 catch per tow was greater or lesser than the 

 median. In this manner it was possible to compare 

 degree squares without considering the actual 

 abundance of larvae. The degree square data indi- 

 cated that in every instance except one the same 

 degree squares for each year were consistently 

 good or poor. 



I assumed therefore that the distributions were 

 not random and that the data for the two sampling 

 years could be combined for analyzing larval 

 distribution. 



The combined data on distribution of larvae in 



1969 and 1970 are presented by time periods 

 (usually semimonthly) between 29 March and 21 

 September (Figures 1 to 7). Most of the larvae 

 were in the southern and eastern portions of the 

 study area and within these areas were most 

 abundant close to shore. The largest catches (more 

 than 1,000 larvae under 10 m^ of sea surface) 

 were made near Unimak Pass and Port Moller; 

 the smallest (usually fewer than 10 larvae under 

 10 m^ of sea surface) were generally made in the 

 more central and western parts of the area. 



The distribution and abundance of larvae in the 

 Black Hills-Port Moller area increased gradually 

 toward the head of Bristol Bay. During the first 

 half of May (Figure 2), larvae were found off the 

 Black Hills area; 2 wk later (Figure 3), these lar- 

 vae apparently had been carried northeastward 

 along the coast and became mixed with larvae 

 released off the Port Moller area. As the season 

 continued, the center of abundance shifted farther 

 toward the head of the bay (Figures 4 and 5). This, 

 trend continued until mid-July (Figure 6), when 

 no more larvae were taken (Figure 7). 



The seasonal progression of occurrence of larvae 

 off Unimak Island is less clear. A small concentra- 

 tion of larvae was found in this area in early May 

 (Figure 2); 2 wk later they were most abundant to 



810 



