330 
Fishery Bulletin 95(2), 1 997 
composition and sex ratio throughout their distribu- 
tion. Due to the opportunistic nature of obtaining 
samples, only the portion of the population available 
to fisheries and research vessels was sampled. These 
are likely the larger animals, i.e. the mature individu- 
als of the population. Therefore the results of length 
and age at maturity could be overestimated. Addition- 
ally, during the time of sex segregation the samples 
may be biased towards more females, since the males 
may be unavailable for sampling. Until the population 
distribution over time and space is better understood, 
it will be difficult to design sampling schemes that will 
yield unbiased population parameters. 
Egg stage development for Atka mackerel is simi- 
lar to that described for the masked greenling 
(Hexagrammos octagrammos ) (Munehara et al., 
1987; Munehara and Shimazaki, 1989). Oogenesis 
in Atka mackerel exhibited the following sequence: 
Table 4 
Length and age at maturity for Atka mackerel. 
Area 
a 
S(a) 
P 
S(p) 
L 50% 
95% Cl (low) 
95% Cl (upper) 
Var (L 50%) 
Gulf of Alaska 
-27.16 
3.69 
0.71 
0.09 
38.24 
36.27 
40.21 
1.00 
Eastern Aleutians 
-25.50 
3.57 
0.71 
0.09 
35.91 
33.94 
37.90 
1.01 
Central Aleutians 
-23.83 
3.67 
0.71 
0.09 
33.55 
31.12 
36.57 
1.54 
Western Aleutians 
-23.89 
3.68 
0.71 
0.09 
33.64 
31.20 
36.69 
1.55 
Area 
a 
S(a) 
P 
S(p) 
Age 50% 
95% Cl (low) 
95% Cl (upper) 
Var (Age 50%) 
Areas combined 
-7.33 
0.87 
2.03 
0.22 
3.60 
3.40 
3.81 
0.01 
