676 



Fishery Bulletin 103(4) 



20 40 60 



Age class 



80 



20 



40 60 80 



Age class 



20 



40 60 



Age class 



80 



20 30 



40 50 60 

 Length (cm) 



70 



Figure 3 



Observed lengths at age for (A) female and (B) male silvergray rockfish 

 tSebastes brevispinis). Predicted length-at-age for (C) females, males, and both 

 sexes combined; and (D) weight at length for females ("+") and males ("o"). 



Fecundity and stock-assessment-parameter estimates 



The total number of large oocytes ranged from 181,000 

 to 1,917,000 (Fig. 8). A general linear model (GLM) 

 treatment of log fecundity against log somatic weight 

 and age indicated that age was not a significant variable 

 after accounting for somatic weight. Although size is a 

 better predictor of fecundity than age, we also provide 

 the predicted fecundity with age (Table 5 1 for subsequent 

 calculation of SSB/R. 



We examined histological cross-sections from 11 ma- 

 ture specimens in the sample. All appeared to be late 

 in the process of vitellogenesis, the late stage 3 of Wylie 

 Echeverria (1987) or stage V of Bowers (1992). The oo- 

 cytes in each ovary were either large, with diameters 

 ranging from 300 to 600 ftm or smaller than 150 f.i. 



There was little variation within ovaries in the dia- 

 meter of the larger eggs (± 50 f<m) and thus no evidence 

 of additional maturing batches. 



The SSB/R analysis indicated that an instantaneous 

 fishing mortality (F) that reduces the SSB/R to 50% of 

 what could be expected with no fishing, (F 60% ) equates 

 to an F of 0.072 (Fig. 9). 



Discussion 



Data sources 



The opportunistic assemblage of samples collected from 

 the commercial fishery and research cruises has two 

 implications if one attempts to draw inference from these 



