Gonadal structure and population characteristics of the protogynous goby Coryphopterus glaucofraenum

University of Puerto Rico
Marine Biology (Impact Factor: 2.39). 04/1992; 113(1):1-9. DOI: 10.1007/BF00367632


Protogynous hermaphroditism has been reported in two gobiid species within the genus Coryphopterus, including C. nicholsi from the temperate northeastern Pacific and C. personatus from the Caribbean. In a third species from the Caribbean, C. glaucofraenum, experimental groups were established and gonad structure of experimental individuals (collected off the southwest coast of Puerto Rico between February 1985 and June 1987) was subsequently examined histologically to determine the sexual pattern. Protogyny was confirmed in C. glaucofraenum. Sex change was either initiated or completed, typically by the largest female, in all-female groups held for 10 to 40 d. Ovarian, transitional, and testis structure were similar to that of C. nicholsi and C. personatus. No preformed testicular tissue was evident in the ovary proper and ovarian features were not retained in the sex-changed testis beyond the newly transformed stage. Secretory accessory gonadal structures associated with the testis and which develop at the time of sex change arose from precursive tissue masses associated with the ventral portion of the ovarian wall in the region of the common genital sinus. The rapid development and onset of function in these structures, generally preceding that of the associated developing testis, suggest that they may play an important role in sex change events and in advertising new male status. Based on observed similarities of ovarian, transitional and secondary testis structure in three protogynous Coryphopterus species, including one species isolated since the last closing of the American landbridge, it is probable that protogyny is an ancestral condition in this genus.

4 Reads
  • Source
    • "Both species feed on sand-dwelling meiofauna and use crevices at the reef/sand interface or in coral rubble as refuges from predators , as well as for nest sites (Forrester and Steele 2004; Forrester et al. 2006). In the Bahamas, these fish reach a maximum of 60 mm SL (Cole and Shapiro 1992; Forrester et al. 2006), and they inhabit home ranges no greater than a few square meters (Marsh 2003; Forrester et al. 2006). Cooccurring groupers (i.e., E. striatus, Cephalopholis fulva, and C. cruentata) were previously common predators of both species of goby (Albins 2012; Slattery, Gochfeld and Marsh-Hunkin pers obs), although their current effect is less clear due to increased fishing pressure and competition (Albins and Hixon 2012). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Understanding prey response to predators and their utilization of sensory cues to assess local predation risk is crucial in determining how predator avoidance strategies affect population demographics. This study examined the antipredator behaviors of two ecologically similar species of Caribbean coral reef fish, Coryphopterus glaucofraenum and Gnatholepis thompsoni, and characterized their responses to different reef predators. In laboratory assays, the two species of gobies were exposed to predator visual cues (native Nassau grouper predator vs. invasive lionfish predator), damage-released chemical cues from gobies, and combinations of these, along with appropriate controls. Behavioral responses indicate that the two prey species differ in their utilization of visual and chemical cues. Visual cues from predators were decisive for both species’ responses, demonstrating their relative importance in the sensory hierarchy, whereas damage-released cues were a source of information only for C. glaucofraenum. Both prey species could distinguish between native and invasive predators and subsequently altered their antipredator responses.
    Marine Biology 04/2013; 160(4). DOI:10.1007/s00227-012-2156-6 · 2.39 Impact Factor
  • Source
    • "Bridled gobies occur on coral reefs throughout the Caribbean . They have planktonic larvae that settle on reefs at 6.5–8.0 mm SL (Sponaugle and Cowen 1994) and are protogynous hermaphrodites, maturing as females once they reach 22–25 mm SL (Cole and Shapiro 1992). The sex change to male can occur at 28 mm, but typically occurs at 35–40 mm SL. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We tested for density-dependent reproduction in a small coral reef fish using field manipulations of density and observational data. Males of the study species, the bridled goby (Coryphopterus glaucofraenum Gill), defend benthic nest sites, within which they spawn with females, and females can spawn repeatedly over an extended breeding season. In small areas, usually only a single male nested at any one time regardless of how many males were present, so the probability of nesting was inversely proportional to density. Nesting males were almost always the largest in the vicinity, suggesting that, for males whose home ranges overlap, social interactions dictate opportunities to nest. Both the per capita rate at which clutches were laid and the number of eggs produced per clutch declined with increasing density, so the per capita rate of egg production was also density dependent. All three measures of fecundity were better predicted by numerical density (numbers per unit area) than biomass (mass of fish per unit area), and were well described as an inverse function of the number of gobies in the vicinity. A simple hypothesis consistent with these results is that a constant number of females spawn, regardless of density. Alternately, the effect of crowding may depend primarily on the number of interacting individuals and affect all females relatively equally. This density dependence could thus contribute to population regulation at the spatial scale over which populations become reproductively closed. KeywordsAdults-Fecundity-Marine-Population density-Population regulation
    Population Ecology 01/2011; 53(1):155-163. DOI:10.1007/s10144-010-0225-6 · 1.57 Impact Factor
  • Source
    • "Larvae settle to reef habitats at 6.5–8 mm standard length (SL) after roughly 30 d in the plankton. Juveniles mature into females at 22–25 mm SL and can change sex to become males at ;30 mm SL (Cole and Shapiro 1992). The largest individuals reach 50–55 mm SL, and very few live beyond a year. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Various predator-prey, host-pathogen, and competitive interactions can combine to cause density dependence in population growth. Despite this possibility, most empirical tests for density-dependent interactions have focused on single mechanisms. Here we tested the hypothesis that two mechanisms of density dependence, parasitism and a shortage of refuges, jointly influence the strength of density-dependent mortality. We used mark-recapture analysis to estimate mortality of the host species, the bridled goby (Coryphopterus glaucofraenum). Sixty-three marked gobies were infected with a copepod gill parasite (Pharodes tortugensis), and 188 were uninfected. We used the spatial scale at which gobies were clustered naturally (approximately 4 m2) as an ecologically relevant neighborhood and measured goby density and the availability of refuges from predators within each goby's neighborhood. Goby survival generally declined with increasing density, and this decline was steeper for gobies with access to few refuges than for gobies in neighborhoods where refuges were common. The negative effects of high density and refuge shortage were also more severe for parasitized gobies than for gobies free of parasites. This parasite has characteristics typical of emerging diseases and appears to have altered the strength of a preexisting density-dependent interaction.
    Ecology 06/2006; 87(5):1110-5. DOI:10.1890/0012-9658(2006)87[1110:PAASOR]2.0.CO;2 · 4.66 Impact Factor
Show more