102 



Fishery Bulletin 97(1), 1999 



excised from the ovarian membrane and placed 

 in Gilson's solution (equal parts concentrated 

 glacial acetic acid, chloroform, and 60% ethanol) 

 for about three months and shaken periodically 

 to loosen them from ovarian tissue. Before count- 

 ing, the ovaries were repeatedly washed and the 

 egg masses broken up to remove remaining con- 

 nective tissue. The resulting eggs were weighed; 

 the subsamples were removed and also weighed. 

 Eggs in each subsample were counted and the 

 mean number per weight calculated for each 

 subsample. Egg production, F, was estimated by 

 the calculation 



{TWy.SN)l(SW), 



where TW ~ total weight of gonads; 



SN = mean subsample egg number; and 

 SW = subsample weight. 



Results 



Age and growth 



For each species, the von Bertalanffy parameters 

 were estimated for males and females separately, 

 and for both sexes combined. An ANOVA was 

 used to statistically compare the amount of vari- 

 ance described by both the separate and combined 

 growth curves. ANOVA results concluded that for 

 both grass rockfish (F=1.16, P>0.05) and brown 

 rockfish {F=1.15, P>0.05) there was no significant 

 difference in the amount of variance explained by 

 estimating sex-specific values for the three param- 

 eters. Thus, for each species growth of both sexes 

 is adequately depicted by a single growth curve. 



The von Bertalanffy parameters for grass rock- 

 fish wereL.= 51.3 cm, ^= 0.11, <o= -2.41 (Fig. 1) 

 and for brown rockfish L^ = 51.4 cm, k - 0.16, f^ 

 = -0.55 (Fig. 1). As with other rockfishes, imma- 

 ture fishes grew relatively rapidly slowly as they 

 matured. Within each species, sexes appeared to have 

 similar life spans. The oldest male grass rockfish was 

 22 yr, the oldest female 23 yr. Male brown rockfish 

 lived to 18 yr, females to 20 yr 



Length-weight relationships 



For both species, the relationship between total 

 length and weight fitted the relationship 



where W 



weight in grams; 



60- 



50 



40- 



30 



20- 



10- 



.f^° 



grass rockfish 



o Male 

 X Female 



"1 1 1- 



5 



10 



1^ 

 15 



~\ I 1 



20 25 



60- 



50- 



40- 



30- 



20- 



10- 



brown rockfish 



o Male 

 X Female 



— I 



10 



Age (years) 



15 



20 



-> 1 



25 



Figure 1 



Von Bertalanffy growth curves for grass rockfish (S. rastrelliger) 

 and brown rockfish {Sebastes auriculatus) from southern California. 



L = total length in centimeters; and 

 a and b - constants. 



Parameters were estimated with Fishparm v. 3.0 

 (Saila et al. 1988) by using Marquardt's algorithm 

 for nonlinear least squares parameter estimation. 



To test for differences in the relationships between 

 sexes, male and female data within a species were 

 modeled separately. Each relationship was then logj^- 

 transformed to create a linear equation, and slopes 

 of the male and female models were compared by 

 using Student's /-test. This process was repeated with 

 gonad weight subtracted from total body weight, to 



