FISHERY BULLETIN: VOL. 85, NO. 2 



1981 



37 



79 



145 



1 



168 



I 



92 



NOV DEC 



1982 



20 





29 



OCT NOV DEC JAN FEB MAR APR 



DEC JAN 



OCT NOV DEC JAN FEB MAR APR 



226 



1985 



619 



189 



525 ^ 



i 



189 



339 



MAR APR 



Sebastes goodei 



Figure 9.— Percent of mature female Sebastes goodei containing 

 eyed larvae for the reproductive months during 1981-85. Total 

 number of mature females observed are indicated over bars. 



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QC 

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40 T 

 30 

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40 

 30 

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40 

 30 

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40 



30 



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50 

 40 

 30 

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1981 



118 



1982 



16 



123 



85 



31 



96 



14 



13 



Sebastes paucispinis 



Figure 10.— Percent of mature female Sebastes patuyispinis con- 

 taining eyed larvae for the reproductive months during 1981-85. 

 Total number of mature females observed are indicated over bars. 



of time and elaborate displays to induce ovulation 

 are not necessary. It is not surprising, therefore, 

 to find so little information regarding mating be- 

 havior in the most speciose and populous group of 

 fishes in north-central California (Helvey 1982). 



Ages and sizes at maturity from this study gen- 

 erally agree with findings in the literature, but some- 

 times exhibit large discrepancies (Table 8). The 

 variability has possible sources: differences in age 

 determination techniques, length measurements, 

 identification of the immature gonad stage, or sam- 

 pling at times of the year when it is difficult to 

 distinguish immature from resting fish. Previous 

 studies on maturity often focused on adult popula- 



tions or were based on samples taken only during 

 summer, when most species are not in reproductive 

 condition (Westrheim 1975; Gunderson et al. 1980; 

 Rosenthal et al. 1981, 1982). The differentiation of 

 an immature gonad stage versus mature "resting" 

 gonads is most difficult and subject to error during 

 the nonreproductive months. 



Age and size at 50% maturity by area and year 

 were calculated for S. Jlavidus, S. goodei, and S. 

 paucispinis (Table 9). Age and size at maturity did 

 not differ geographically but did vary between 

 years. Age varies up to 1 year and size varies up 

 to 3 cm. Apparently, there is some variability in age 

 and size at maturity within a population between 

 years. The normal range of variation of size and age 



246 



