Hoff. Biology and ecology of Gymnocanthus pistilligei in the eastern Bering Sea 



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these years, catches peaked in Togiak Bay (CPUEs of 71 

 to 79) at some of the shallowest depths trawled (13-15 m). 

 Trawls conducted in Togiak Bay again in 1995, during late 

 May, resulted in densities up to 249 at 19.8 m in depth 

 (11=29, trawls, CPUEs from 4 to 249, .v=65.68, SD=74.68, 

 depth range: 4-30 m). 



Age and growth 



A von Bertalanffy growth curve was fitted to pooled length- 

 at-age data for 1997b and 1998 and analyzed separately 

 for males and for females (Fig. 5). The growth models were 

 the following: 



males L, = 165.5 11^-0.37.5299 (/ + o,07043iii] 



(«=395, r2=0.78,SE=8.08); 



years; males reached 160 mm and a maximum age of 10 

 years. 



Age gi'oups from 1997 consisted of 2- to 10-year-old fish; 

 the strongest age group was 4 years (>50'7f of individuals) 

 and there were large groups of 2- and 3-year-old fish. In 

 1998 however, ages ranged from 3 to 9-year-old fish. The 

 strongest age group (>50'7f of individuals) was 5 years. 

 Two-year-old fish were absent (Fig. 6). Length-frequency 

 histograms (Fig. 7) for 1997 and 1998 male and female G. 

 pistilliger show the age modes as well as the age groups 

 that were absent in 1997 and 1998. 



Weight-length relationships for males and females and 

 between years showed no significant difference (P>0.05) 

 and were pooled for analysis (Fig. 8). The pooled weight- 

 length equation was statistically significant (P<0.01, 

 r-=0.97,/!=992): 



females L, = 223.8 [1^-0228048 (/ + 02266261] 



(n=595, r-=0.84, SE=9.85). 



Females grew faster than males, and by three years of 

 age, a difference in length at age was established (Fig. 5). 

 Females reached >200 mm TL and a maximum age of 9 



TFW igm) = 2.40317 x \Q-^TL (mm)^^^^^^ 



Ovaries were not developed in June when fish were col- 

 lected; few large females contained residual eggs from the 

 previous spawning. The GSI ranged from 0.5% tol.9% for 

 fish collected from 1997 (females /! = 108, 70-190 mm TL). 



