MALE 



FEMALE 



SEXES COMBINED 



3N 



3S 



3 



slope 



2 



slope 



Outer shelf and slope 



s 









S is 









Q. 10 







Mean length=15.7 



5 









\s^ . 



n=934 



Mean length=16.9 

 n=1661 



010XX4J5060 70BOX100 01020X43X60 70 SOX 100 10 20X41X60 70 80X100 

 30 ♦ 30 t 30 



25 .. 



if is I 



0) 



Q- io 

 5 

 



25 .. 



20 . 

 IS 



Mean length=33.9 10 

 n=6286 



25 . 



20 . 



15 . 



Mean length=34.2 10 .. 

 n=4618 



— 



Mean length=273 

 n=15.418 



01020304)5083 70 8030100 01020304)5060 70 9090 100 10 X X 4) 50 60 70 80 X 100 

 33 , 30 + 30 



25 



20 



Mean length=46.6 l5 

 n=213 10 



5 .. 



Mean length=45.1 

 n=316 



10 20304350S3 70 8090100 01OXX43S60 70B0X100 01020X4)5060 70 9390 100 

 30 ♦ 30 t 30 



25 . 



*- 20 .. 

 C 



o is 



5 ., 

 



Mean length=36.8 

 n=8382 



25 



20 ., 

 15 ,. 



Mean length=36.2 

 n=6248 



Mean length=36.0 

 n=15.419 



10 20X4)5050 70 8090100 01020X4)5060 70 80X100 10 20304)50a)70XX100 

 30 , X . X t 



25 



^ 20 

 <u 



0) 



IS . 

 10 



5 .. 

 D 



25 



X 



Mean length-40.4 15 



"= 1110 10 l 



5 



25 . 

 X 



Mean length=44.4 IS 

 n=1985 



10 



S , 



_ c 



Mean length=42.9 

 n=3095 



01DXX41506C70 93X100 010XX4)50B0 70 80X100 01020X41X60 70 80X100 



Fork length(cm) Fork length (cm) Fork length(cm) 



Figure 29. — Size composition of walleye pollock taken during the 1976 Bering Sea spring trawl survey, by sex 

 and geographical area (see Fig. 3). The category sexes combined includes male, Female, and undetermined. 



of age groups within the different sets of data was determined. 

 Because only a limited number of age determinations was ob- 

 tained from otolith area A, observations from otolith areas A and 

 B were combined for analysis. 



Results of the growth curve fittings are summarized in Table 25 . 

 Overall, females showed a slightly higher growth completion rate 

 (see Equation (24)) than males and approximately 8% larger 

 asymptotic length (Fig. 32). 



Comparisons of growth characteristics between geographical 

 regions are shown in Figure 33. For walleye pollock, comparisons 

 between otolith areas A and B (combined) and otolith area D cor- 

 respond to comparisons between populations northwest and 

 southeast of the Pribilof Islands. Both males and females had 



higher growth completion rates and larger asymptotic lengths in 

 the southeastern geographical region. 



Reproductive condition. — Previous studies of the reproductive 

 biology of eastern Bering Sea walleye pollock have reported 

 spawning to occur seasonally (March to mid-July), with peak 

 gonad development and spawning behavior occurring in May 

 (Serobaba 1968, 1971, 1974). Because the spring 1976 survey pro- 

 vided good coverage of this seasonal time period, one of the 

 survey objectives was to assess the reproductive condition of the 

 walleye pollock population within the study area. 



A total of 2,379 males and 3,585 females were examined for 

 gonad condition during the 1976 spring survey. The frequency 



42 



