WENNER ET AL.: LIFE HISTORY OF BLACK SEA BASS 



tion of South Atlantic Bight C. striata at the time 

 the studies were conducted. 



Reproduction 



Smith (1965) established a phylogeny of serranid 

 fishes based on three types of hermaphroditism. 

 Most primitive is the Serranus-type gonad found in 

 Serranus and Hypoplectus, genera which are simul- 

 taneously hermaphroditic with male and female ger- 

 minal tissues well separated by connective tissues. 

 The middle type of this trio is the protogynously her- 

 maphroditic Rypticus-Anthias-type gonad where 

 testicular takeover commences with proliferation of 

 preexisting spermatogonia located in crypts along 

 the alamellar regions of the ovary and gametogenic 

 tissues remain separated by connective tissue 

 throughout sexual transition. Most advanced is the 

 protogynous hermaphroditic Epinephelus-type 

 gonad where testicular tissue cannot be found before 

 sexual transition commences. During this process, 

 crypts of spermatogonia differentiate and prolifer- 

 ate within the ovarian lamellae where they are inter- 

 mixed with oogonia and oocytes. 



Citing Lavenda (1949), Smith (1965) classified C. 

 striata within the Epinephelus-type, an error cor- 

 rected by Mercer's (1978) demonstration that mor- 

 phological events during sexual transition in C. 

 striata most resemble those of the Rypticus- 

 Anthias-type gonad. Sexual succession in C. striata 

 results from hypertrophy of bands of testicular 

 primordia that lie along borders of the alamellar 

 region of the ovary, not the proliferation of crypts 

 of tissue that Mercer (1978; see also Smith 1965) 

 reported. The arrangement of the primordial tes- 

 ticular ridges in C. striata is the same as in the pro- 

 togynous Hemanthias vivanus (Hastings 1981). 



The testicular primordia in C. striata is located 

 in a similar region of the gonad as is the testicular 

 portion of the simultaneously functioning gonad of 

 Serranus tigrinus (Smith 1965). Though not stated 

 by Smith (1965), the testes of S. tigrinus might 

 border the alamellar region of the ovarian section 

 as does the testicular primordial cells in C. striata, 

 a gonadal similarity also noted between H. vivanus 

 and S. tigrinus (Hastings 1981). No phylogenetic in- 

 ferences should be drawn from these data, because 

 gonadal development varies even among the close- 

 ly related simultaneous hermaphrodites of the 

 genera Serranus and Diplectrum. Centropristis 

 striata, H. vivanus, and probably R. maculatus (see 

 Smith 1965) have similar gonadal morphologies and 

 strategies of sex succession, but these species are 

 usually not considered closely related. Gonadal mor- 



phologies may one day be important in determin- 

 ing serranid phylogenetic relationships, but more 

 observations of all serranids are necessary. 



The simultaneously functioning gonad of C. 

 striata has morphology similar to that of Serranus 

 (Smith 1965) in which discrete areas of testicular 

 tissue empty into peripherally located sinuses, and 

 oocytes discharge centrally. Sperm sinuses within 

 the wall of the simultaneous gonads are well 

 developed in C. striata, but it is not known if they 

 are functional, i.e., permit sperm to exit the body 

 along with the oocytes. 



We found sizes and ages of C. striata undergoing 

 sex succession which were similar to those Mercer 

 (1978) reported in the South Atlantic Bight; how- 

 ever, we found a much higher incidence of transi- 

 tional fish. Since Mercer (1978) found only 4% of 

 C. striata from this area were undergoing sex suc- 

 cession, she offered two mechanisms for her abun- 

 dance (38%) of mature males: 1) development of 

 mature males from both immature males and 

 juvenile hermaphrodites was very important, or 2) 

 the rate of sexual transition was very rapid in this 

 species. 



We feel that both of Mercer's arguments were at 

 best incomplete because of her small sample sizes 

 from the South Atlantic Bight. Since we found few 

 immature males and juvenile hermaphrodites in our 

 samples, the probability is low that mature males 

 develop solely from these. Also, we acknowledge the 

 presence of serranids which show rapid sex succes- 

 sion (Fishelson 1970; Fricke and Fricke 1977) and 

 believe the low frequency of individuals undergoing 

 sex succession seen in most Epinepheline groupers 

 probably reflects a similarly short-lived process. 

 However, the presence of C. striata undergoing sex 

 succession throughout the year, and their occur- 

 rence at sizes where the frequency of females 

 declines, leads us to conclude that the primary 

 source of mature males is through sex succession 

 from active females. 



We found secondary testes (sensu Harrington 

 1971) in all male C. striata including immature 

 specimens. This morphology is not unique to C. 

 striata. Hastings (1981) observed no primary male 

 H. vivanus and suggested they all passed through 

 an initial female phase. This same secondary gonadal 

 morphology occurs in the secondarily gonochoristic 

 serranid Paralabrax clathratus (Smith and Young 

 1966), and Reinboth (1970) indicated all male ser- 

 ranids are derived from females. 



Overall, sex ratios of C. striata were significantly 

 different from an hypothesized la:l9 in favor of 

 females. Females significantly outnumbered males 



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