424 



Fishery Bulletin 102(3) 



300 



200 " 



100 



L = 442.02 •( 1 -e 1 " ° 33 ' (a9e " ( ° 75 1") 



10 15 20 



Age (years) 



Figure 5 



Fork length at age fitted to the von Bertalanffy growth model for female 

 black rockfish. 



(2-tailed i-test, P<0.0001,) of a stage effect 

 (i.e., unequal elevations) which necessitated 

 that the data be fitted with a parallel-line 

 multiple linear regression model (Fig. 10 1. 



Temporal patterns in parturition 



From 1996 through 1998 we estimated rela- 

 tive larval production for four age groups: 

 6-8; 9-11; 12-14: and 15 years and older 

 (Fig. 11). In each year parturition took place 

 from mid-January until mid-March, and 

 older, larger fish extruded larvae earlier 

 than younger fish. In 1996 and 1997, the 

 9-11 year-old fish dominated larval pro- 

 duction, responsible for 60. lQ and 49. 6^ of 

 all larvae extruded, respectively (Table 5). 

 In 1998 age 6-8 fish produced the largest 

 percentage of larvae (65.3%). In all years, 

 relative larval production was lowest for the 

 oldest age group (15+), declining to near 

 by 1998. 



Discussion 



P= 0.096). There was, however, strong evidence (2-tailed 

 /-test, P<0.001,) of a stage effect li.e., unequal elevations) 

 which necessitated that the data be fitted with a paral- 

 lel-lines multiple linear regression model (Fig. 9). 



Absolute fecundity for prefertilization female black 

 rockfish ranged from 443.671 oocytes for a 381-mm-FL 

 female to 1,135,457 oocytes for a 495-mm-FL female. 

 For fertilized females, absolute fecundity ranged from 

 283,618 oocytes for a 381-mm-FL female to 1,073,356 

 oocytes for a 510-mm-FL female. The results of AN- 

 COVA over a common size range showed no evidence of 

 differences in slopes between maturity stages (2-sided 

 /-test P=0.206). There was, however, strong evidence 



Ovarian development for black rockfish in Oregon was 

 similar to the developmental cycles reported for other 

 rockfish species (Moser, 1967; Bowers, 1992; Nichol and 

 Pikitch, 1994) with the exception of seasonal timing 

 and stage duration. Females underwent vitellogenesis 

 for up to six months before fertilization, which occurred 

 from December through February. In all three years, 

 parturition off the Oregon coast occurred between mid- 

 January and mid-March and peaked in February. Wyllie 

 Echeverria (1987) observed similar timing for parturi- 

 tion of black rockfish off north-central California, with a 

 peak in February but with parturition occurring through 

 May. 



