WARNER: REPRODUCTIVE BIOLOGY OF PIMELOMETOPON PULCHRUM 



year-round condition in its presumably tropical 

 ancestor, representing an adaptation to the fluc- 

 tuations of food availability characteristic of 

 temperate regions. 



The size-specific increases in fecundity seen in 

 Catalina P. pulchrum are, of course, common in 

 most long-lived fishes. Many of the Guadalupe 

 females vv^ere not sexually active when the sample 

 v^^as taken and no fecundity data are available. 

 However, it can be predicted that the average 

 fecundity of Guadalupe Island individuals will 

 increase much more slowly with age than that of 

 individuals from Catalina, due to the low growth 

 rate of the Guadalupe individuals discussed in an 

 earlier section. If the active ovary weight 

 increases with size in a fashion similar to that seen 

 at Catalina (Figure 13), the average ovary weight 

 for a 4-yr-old fish at Guadalupe would be 

 approximately 8 g. Age class 4 California 

 sheephead at Catalina had ovaries with an average 

 weight of 13.13 g. The difference increases with 

 age. Six- and eight-year-old individuals at 

 Guadalupe should have ovaries weighing 9 and 15 

 g respectively. Weights for the same ages at Cat- 

 alina were 23.1 g and 53.5 g. 



In the Catalina population, there may be an 

 abrupt increase in the fecundity of fishes remain- 

 ing female after age seven; this is the age where 

 most sexual transformations occur (compare 

 Figures 9 and 14). If such an increase does exist, it 

 may be an indication of compensation by those 

 remaining females for the relative gain in age- 

 specific reproductive potential experienced by in- 

 dividuals that do change sex. A more complete 

 discussion of relative male and female age-specific 

 fecundities can be found elsewhere (Warner in 

 press). 



the Labridae, and extensive sampling is usually 

 needed before the relationship between sex and 

 coloration can be accurately described. 



Many labrid species exhibit a number of color 

 phases, and these have often been attributed to 

 sexual dimorphism or to differences between im- 

 matures and adults. Roede (1972) has reviewed a 

 number of cases where such an interpretation was 

 incorrect, being based on casual observation or 

 small samples. Apparently there is no strict dis- 

 tribution of sex with color in the Labridae and the 

 only generalization possible is that females tend to 

 strongly predominate in the "first adult" (Roede 

 1972) colors, and the terminal-phase coloration is 

 made up almost exclusively of males. 



In most species investigated, males make up 10 

 to 35% of the first adult-colored individuals (Roede 

 1972). In Gomphosus varius (Strasburg and Hiatt 

 1957), Halichoeres maculipinna, H. garnoti, and 

 Hemipteronotus martinicensis (Roede 1972), no 

 males are found in the initial color phase. In con- 

 trast, Soljan (1930a, b) found that 48% of the 

 Symphodus (Crenilabrus) ocellatus examined in 

 the first adult phase were males. 



The terminal-phase coloration appears to be 

 much more closely restricted as to sex. Of 14 labrid 

 species exhibiting color phases mentioned by 

 Roede (1972), the terminal phase consisted 

 exclusively of males in all but two {Halichoeres 

 garnoti and H. bivittatus). When other coloration 

 classes are described, intermediate between the 

 initial and terminal phases, the proportions of 

 males and females in them are also intermediate. 

 Roede (1972) notes that where color changes are 

 more gradual, as in H. garnoti and H. bivittatus, 

 the relationship between size and sex is the least 

 exact. 



The Relationship of Color and Sex 



Pimelometopon pulchrum appears to follow the 

 general labrid coloration pattern quite closely, 

 with a preponderance of females and immatures 

 in the initial uniform color phase, and the terminal 

 bicolored phase containing only males. Thus the 

 designation of the uniform phase as the "female" 

 coloration and the bicolored phase as the "male" 

 coloration (Jordan and Evermann 1898; Fitch and 

 Lavenberg 1971; Miller and Lea 1972) is more or 

 less correct, especially when immatures are 

 included under the uniform designation (Barnhart 

 1936; Roedel 1948). Dichromatism, however, is not 

 necessarily an indication of sexual dimorphism in 



Sex Ratio and an Estimate of Survival 



Roede (1972) believed that her collections were 

 true random samples of populations and was able 

 to estimate the sex ratio in the seven labrid species 

 she investigated. There were two to four times as 

 many females as males in all but one species 

 {Hemipteronotus splendens), which had an equal 

 sex ratio. 



The samples of P. pulchrum were not considered 

 random and direct sex ratio estimates could not be 

 made. Field transects at Catalina and Guadalupe 

 islands yielded a ratio of about 5.5 uniformly 

 colored individuals to every bicolored male. To es- 

 timate the sex ratios of mature individuals, the 



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