736 



Fishery Bulletin 88(4). 1990 



(r 

 o 



5 



10 12 14 16 18 20 



HOURS 



B TANNER CRAB 



Figure 2 



Logistic regression of immediate mortality vs. total time spent in 

 captivity. Crabs were grouped into 1-hour intervals before analysis. 

 (A) 6 1 13 observations representing 7487 individuals. (B) 4645 obser- 

 vations representing 16498 individuals. Squares are observed data, 

 solid lines represent predicted values. 



tr 

 o 



tr 

 O 



2 



A KING CRAB 



10 15 20 25 30 35 40 



TONS 



5 to 15 20 25 30 35 40 



TONS 



Figure 3 



Logistic regression of immediate mortality vs. total weight of catch. 

 Crabs were groujied into 1-t intervals liefore analysis. Squares are 

 observed data, solid lines represent predicted values, which were 

 incalculable for B. 



had been tagged, held for observation, and released 

 was recaptured with its tag still attached. Others may 

 have been recaptured as well, but since most of the tags 

 were removed prior to discarding the crabs, they could 

 not have been identified as recaptures. 



Effects of time in captivity and weight of catch 



CAPTIME, the total time in captivity (prior to vitality/ 

 injury assessment) ranged from 3 to 17 hours (Fig. 2). 

 The logistic fitting procedure indicated a significant 

 relationship (/■- = 0.878, « = 13, a<0.0()l) between 

 CAPTIME and immediate mortality of king crabs (Fig. 

 2A); the relationship for Tanner crabs (Fig. 2B) was 

 weaker but still significant (r- = 0.603, >i=ll, o = 

 0.05). The LT,=,o's (time required for 50% immediate 

 mortality) were 9.3 hours for king crabs and 8.3 hours 

 for Tanner crabs. 



Haul weights ranged from 4 to 39 t (^ = 20.4 t). The 

 relationship between haul weight and immediate mor- 



tality for king crabs (Fig. 3A) was poor and non-sig- 

 nificant (r- = 0.245). The relationship for Tanner crabs 

 was so poor (Fig. 3B) that the iterative fitting pro- 

 cedure could not converge on a solution. 



Shell conditions 



Soft shell or molting crabs (shell condition 1) accounted 

 for only about 1.1% of male king crabs, and <().\% of 

 females. All other females and most males were hard- 

 shell crabs (condition 2). About 9.4% of males were 

 oldshell crabs (condition 3), and virtually all of these 

 were above 100 mm CL. During the NMFS summer 

 EBS survey in June of 1987 (Stevens et al 1987). 2.8% 

 of males were soft or molting and many others were 

 hardshell but recently molted. Immediate survival odds 

 (ratio of survivors to deaths. Fig. 4) increased signif- 

 icantly (X- = 81.63, p<0.001) with increased shell con- 

 dition, i.e., hardness, but delayed survival was indepen- 

 dent of shell condition (X- = 0.60, />>0.74). 



