74 
Fishery Bulletin 108(1 ) 
The gonadosomatic index (I G ) began increasing in 
November and January, reaching a maximum in March, 
followed by a decrease in April. The lowest value ob- 
served was from one sample collected in June and 
qualitatively appeared to follow the decreasing trend 
(Fig. 4). This increase in I G from late winter to spring 
shows an increase in the ratio of ovary weight to total 
body weight with the development of fertilized ova in 
April. The lowest I G value in June corresponded with 
low ovary weight due to postparturition. The seasonal 
trend of decreasing I G , coupled with the monthly ovary 
development results of this study, indicates May as the 
peak month of parturition for dusky rockfish in the 
central Gulf of Alaska. 
Von Bertalanffy growth parameters for female dusky 
rockfish from the maturity estimate sample were 
L x -449 mm, £ = 0.219, and f 0 =0.855 in contrast to val- 
ues of L x = 480 mm, £ = 0.211, and t 0 =1.106 for females 
from the NMFS GOAS. The female dusky rockfish from 
the NMFS GOAS were slower growing than females col- 
lected for the maturity estimate as reflected by the dif- 
ferent mean asymptotic length and growth coefficients 
