104 



Fishery Bulletin 97(1), 1999 



A A A A A 



Males* 

 *9®50% mai 

 FemalesA 



50% mat 



:3.5yr 



= 3.7yr 



Id 



E 

 c 

 g 

 '■c 

 o 

 a. 



~\ I — I — r 



2 3 4 5 6 

 Age (yr) 



~1 I I r 

 7 8 9 10 



I T I [ 1 1 1 1 1 1 r 



20 21 22 23 24 25 26 27 28 29 30 



Total length (cm) 



Figure 3 



Age-maturity and length-maturity and relation- 

 ships for male (n=88l and female in=14) grass 

 rockfish (Sebastes rastrelliger) taken in the 

 southern California Bight, including estimated 

 ages and lengths at which SO'/f of the fish were 

 mature. Solid and dashed lines represent pre- 

 dicted relationship. 



Fifty percent of males were mature at about 24.5 cm, 

 and fifty percent of females at 24 cm. Male grass rock- 

 fish matured from 2 to 5 yr, females from 3 to 5 yr 



For brown rockfish, there was also little difference 

 between sexes in either length or age at first matu- 

 rity (Table 1). Males matured between 19 and 29 cm, 

 females between 21 and 32 cm (Fig. 4). For males, 

 50% maturity occurred at about 25 cm, for females 

 at 26.4 cm. Age at first maturity for both male and 

 female brown rockfish occurred as early as 3 yr, and 

 all fish were mature by 6 yr (Fig. 4). 



ary (Fig. 5). Females with spawned ovaries were 

 found only during February and March, after which 

 followed a 6-month resting stage. Vitellogenic ova- 

 ries were common from December to February. Ovary 

 indices remained at a minimum throughout spring, 

 summer, and early fall, averaging about 0.3% of body 

 weight, then increased to a peak of 6.8% in Decem- 

 ber ( Fig. 6 ). Testes indices were also low during spring 

 and summer (averaging less than 0.1%), rising to a 

 peak of 0.2% in December (Fig. 6). 



Brown rockfish spawned from January to August, 

 reaching a peak in January (Fig. 5). Although females 

 with resting stage ovaries were found from April to 

 November, most occurred during the summer. We 

 found vitellogenesis-stage ovaries during most 

 months, particularly between fall and spring. For 

 females, gonosomatic indices were lowest (averag- 

 ing 0.6%) from June to November and peaked dur- 

 ing January at 7.1% (Fig. 6). Testicular indices were 

 lowest from March to August (averaging 0.15'^ ) and 

 peaked in October at 0.62% (Fig. 6). 



Spawning seasons 



Grass rockfish released larvae from January to 

 March, reaching a peak in spawning during Janu- 



Fecundity 



The relation between grass rockfish fecundity and to- 

 tal length (Fig. 7) was best described by the function 



