FISHERY BULLETIN: VOL. 73, NO. 2 



through September. Late class 3 gonads were seen 

 in July, August, and September, and most spawn- 

 ing activity probably takes place in these months. 

 Females with postspawning ovaries (class 4) were 

 captured in low numbers from August to early 

 October. Class 4 appears short-lived, quickly 

 receding into a resting class (class 2) or transi- 

 tional (class 5) phase. 



Transitional individuals were found only from 

 October to March at Catalina. Those taken in Oc- 

 tober and November were all in the early stages of 

 transformation, with many stage 2 oocytes and a 

 few scattered spermatogenic crypts in evidence. 

 Transitionals captured in February at Catalina or 

 in May at Guadalupe were more advanced, with 

 few stage 2 oocytes and spermatogenic crypts 

 dominating the gonad. 



Most males at Catalina were inactive (class 6) 

 from October through April, closely paralleling the 

 period seen for females. Active gonads 

 predominated in samples from fish taken in May 

 through September. Again the pattern suggests 

 that spawning activity takes place from August 

 through early October. 



Further support for designating this period as 

 the spawning season comes from the gonad indices 

 (Figure 11) of Catalina females caught in 

 different months. These reflect a similar pattern 

 seen in the analysis of gonad development states. 

 After a quiescent period from October through 

 April, the ovaries begin to increase in size until a 

 maximum is reached in June and July. Spawning 

 reduces the average index steadily from then until 



90 



90 



70 



E 



E 60 



o 50 



z 



o 40 



30 



20 



10 



September. The resting value is then seen again, 

 remaining constant through the winter. 



The index used was gonad weight scaled to 

 compensate for different lengths of individuals. 

 When only the mature females less than 310 mm in 

 standard length are included in the analysis, the 

 relationship between gonad weight and standard 

 weight is sufficiently linear (Pearson correlation 

 coefficient = 0.845 [P < 0.001] on 24 individuals 

 caught in June) that the use of the following for- 

 mula is justified: 



Gonad index = (9°"ad weight in grams) (100) 

 (standard length in mm) 



The size range used includes the great majority of 

 reproductive females at Catalina. 



An analysis of the spawning season of P. 

 pulchrum at Guadalupe Island was not possible 

 due to the lack of year-round sampling. 



Multiple Spawning and Fecundity 



Two or more distinct groups of ripening oocytes 

 were usually apparent in the ovaries of P. 

 pulchrum examined in June and July. The size 

 distribution of yolky oocytes in an ovarian cross- 

 section (Figure 12) from a female, 244 mm SL, 

 captured at Catalina in mid-July, shows that there 

 is one group of eggs ready to be spawned, and that 

 two other distinct groups are undergoing vi- 

 tellogenesis. This type of successive maturation of 

 several groups of oocytes is termed asynchrony, 

 and is characteristic of species that have com- 

 paratively long breeding seasons and multiple 

 spawnings by individuals within each season 

 (Yamamoto and Yamazaki 1961). 



J J 



MONTH 



4 6 8 10 12 14 16 18 



OOCYTE DIAMETER (ocular micrometer units) 



Figure 11. -Average gonad indices for monthly samples of ma- 

 ture female Pimelometopon pulchrum., all of standard lengths 

 less than 300 mm. Sample sizes are shown above the bracketed 

 lines, which are the 95% confidence limits of the mean. 



Figure 12.-Size distribution of yolky oocytes in an ovarian 

 cross-section of a 244 mm SL female of Pimelometopon pulchrum 

 captured 22 July at Catalina Island. The oocytes are also clas- 

 sified according to their degree of development. 



272 



