FISHERY BULLETIN: VOL. 73, NO. 2 



Labroides dimidiatus, and 15 of these had crypts 

 with sperm or spermatids. Thus, the possibility of 

 encountering a synchronously hermaphroditic 

 labrid species should not be ruled out. 



Transformation Schedule 



Pimelometopon pulchrum fits the general labrid 

 pattern of size and sex distribution. No males were 

 found smaller than 230 mm SL at Catalina Island, 

 and none smaller than 150 mm at Guadalupe. The 

 longer size classes (above 350 mm and 230 mm at 

 Catalina and Guadalupe, respectively) contain 

 mostly males. 



Data for labrid sexuality are usually in the form 

 of size frequency distributions of males and 

 females within a species (Atz 1964; Remade 1970; 

 Roede 1972). Some of these studies have been con- 

 founded by the presence of two distinct color pat- 

 terns, the investigators wrongly assuming strict 

 sexual dichromatism (see below). An additional 

 complication is the possibility of two different 

 types of males being present in some species, 

 usually with different life histories and behavior 

 (Reinboth 1970). Both of these problems are 

 eliminated by histological examinations of the 

 gonad, which also reveals the presence of inter- 

 sexual or transitional individuals. 



The absence of males from the smaller size 

 classes at least suggests protogyny. However, 

 similar patterns can also result from samples of a 

 species exhibiting differential growth rates for 

 the sexes (e.g., see Strasburg 1970, for weight and 

 sex distributions of blue marlin, Makaira 

 nigricans), and this should be taken into con- 

 sideration. 



Fourteen of the fifteen labrid species either 

 reviewed or dealt with originally by Roede (1972) 

 had similar patterns of length-sex distribution. 

 Females predominated in the smaller size classes, 

 males in the larger. The proportion of males in the 

 smaller sizes (usually associated with a particular 

 color pattern; see below) varied from practically 

 none in some species of Halichoeres and 

 Hemipteronotus up to nearly 30% for Stethojulis 

 strigivenfer (Randall 1955). Males became 

 increasingly common as length increased and the 

 longest size classes consisted almost exclusively of 

 males. 



Species of the genus Symphodus (Crenilabrus) 

 appeared to exhibit a different pattern, with 

 nearly equal numbers of males and females in the 

 small size classes (Soljan 1930a, b). Remade (1970) 



believed that sex reversal is a rare phenomenon in 

 this genus. 



Age determinations allow several more 

 inferences about the sexual life history of a 

 species. When few or no young males can be found, 

 there is strong evidence for protogyny since the 

 possibility of differential growth is eliminated. 

 The rate of transformation in different age 

 classes can be estimated, and this provides an idea 

 of how long the average individual spends in 

 different sexual phases. Finally, by comparing the 

 distribution of sex versus length with sex versus 

 the age of the individual, it may be possible to 

 assign a more critical role to one or the other as a 

 causative factor for sex reversal. 



The age at first maturity (4 yr) does not differ 

 for P. pulchrum at Catalina and Guadalupe 

 Islands, but the distribution of sexual transfor- 

 mation with age differs markedly. Most in- 

 dividuals in both populations function at least 1 yr 

 as females. At Guadalupe, many change sex after 

 1 yr, and most are males within 3 yr after matur- 

 ing. Most sex reversals occur at Catalina between 

 the seventh and eighth year, 4 yr after maturing 

 as a female. Some individuals remain female for 

 shorter or longer periods of time. The oldest 

 female encountered in this study was 17 yr old. 



The dwarfing phenomenon at Guadalupe, which 

 should bring about a slower rate of increase of 

 fecundity with age, would have enough effect to 

 decrease the optimum age of transformation in 

 that population when compared to the Catalina 

 population. This will be discussed in detail else- 

 where (Warner in press). 



Lonnberg and Gustafson (1937) determined the 

 ages of a series of specimens of Labrus bimacula- 

 tus (as L. ossifagus) which they correlated with 

 sexual state. They found that sex reversal occurred 

 in individuals from age seven onward, and was 

 associated with a color change from red to blue- 

 striped. Females were found in diminishing 

 numbers up to age 18, mostly confined to the red 

 phase. Males in the red phase ranged from around 

 3 to 7 yr old; blue-striped males got as old as 25. 



Other protogynous teleosts which have been 

 investigated regarding age of transformation 

 show a variety of patterns in the distribution of 

 sex reversal over their life-span. Liem (1963) 

 demonstrated that sex transformation in the 

 synbranchid rice eel Monopterus albus occurs 

 mainly when individuals reach about 30 mo of age 

 (about 35 cm in length). Few fishes in nature 

 deviated from this pattern. Liem (1963) was able 



276 



