580 



Fishery Bulletin 94(3), 1996 



gal male RKC. Besides 0.3, we also used M of 0.2, 

 0.4, and 0.5 in our analyses for both populations. In 

 addition, variable natural mortalities — 0.2 for peri- 

 ods of 1974-79 and 1985-93, 0.7 for 1980 and 1983- 

 84, and 1.2 for 1981-82— were used for the Bristol 

 Bay population for comparisons based on our previ- 

 ous work with this stock (Zheng et al., 1995). 



Results 



Bristol Bay red king crab 



Model parameter estimates for Bristol Bay RKC de- 

 pend on natural mortality and weighting factor 



(Table 1). Higher natural mortality generally resulted 

 in a higher total abundance in the first year and 

 higher annual recruitment. Higher weights applied 

 to fishing effort produced larger total RSS, whereas 

 an intermediate weight resulted in the highest RSS 

 contributed by the fishing effort (Table 1). For a 

 weighting factor of one, total RSS were similar and 

 ranged from 23.4 to 24.8 for all fits (Table 1). 

 Catchability coefficient was negatively associated 

 with natural mortality. Selectivity coefficients were 

 less than one for the first length class for all fits and 

 equal to about one for all other length classes. 



The abundances of Bristol Bay legal male RKC 

 estimated from the trawl surveys conducted by 

 NMFS changed dramatically during the last two 



