WARNER: REPRODUCTIVE BIOLOGY OF PIMELOMETOPON PULCHRUM 



3 4 5 6 7 



AGE (YEARS) 



10* 



Figure 9.— Proportions of sexual types in each year class of 

 Pimelometopon pulchrum from Catalina Island (top) and 

 Guadalupe Island (bottom). The last age grouping consists of all 

 fishes 10 or more years old. 



In both populations, sexual maturity begins in 

 the fourth year of life for virtually all members. 

 By using age groupings, the skewness introduced 

 by the dwarfing at Guadalupe is removed, and 

 differences in the transformation activity time 

 schedule in the two populations are revealed. At 

 Guadalupe, males are present in essentially the 

 same abundance as females in age classes 5 and 6, 

 and strongly predominate at age 7 and thereafter. 

 Therefore the majority of California sheephead at 

 Guadalupe Island spend no more than 2 or 3 yr as 

 functional females. 



Transformation generally occurs later in the 

 Catalina population. Most individuals are func- 

 tional females for at least 4 yr, and males 

 predominate only after age 8. 



Distribution of Gonad Development 

 Classes with Time 



The active state of gonads may be determined 

 directly through histological examination or in- 

 ferred from the appearance and the size of gonad 

 (gonad indices). 



The seasonal distribution of mature gonad 



14 



12 



;Class5 



; t. .:■: 



JFMAMJJ ASOND 

 MONTH 



Figure lO.-Number of individuals of Pimelometopon pulchrum 

 in each mature gonadal development class from monthly samples 

 taken at Catalina Island. 



development classes for 166 California sheephead 

 from Catalina is shown in Figure 10. As expected, 

 immature fishes, which are not shown in the 

 Figure, occur throughout the year. Resting stage 

 females (class 2) were encountered from August 

 through May, and predominated from October to 

 April. Active females (class 3) were present May 



271 



