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Protogynous Hermaphrodite (protogynou + hermaphrodite)
Selected AbstractsGrowth and reproductive biology of the foxfish Bodianus frenchii, a very long-lived and monandric protogynous hermaphroditic labridJOURNAL OF FISH BIOLOGY, Issue 3 2010S. Cossington Samples of the foxfish Bodianus frenchii, collected over reefs on the lower west and south coasts of Western Australia, contained individuals ranging up to 78 years old. Although B. frenchii is far smaller than many other species within the Labridae, its maximum age is the greatest yet recorded for this highly speciose family and, together with Achoerodus gouldii, provides an example of a temperate hypsigenyine with exceptional longevity. Length and age compositions of females and males and the histological characteristics of gonads of a wide length range of individuals demonstrated that B. frenchii is a protogynous hermaphrodite. Furthermore, as, on both coasts, the length of the smallest male was greater than that at which all females had become mature, B. frenchii is a monandric protogynous hermaphrodite, i.e. all of its males are derived from functional females. Attainment of maturity by females is related more to length than age, whereas the reverse is true for sex change. On the basis of Schnute growth equations and length-to-body mass regression equations, the predicted length at age and body mass at length of fish on the south coast were greater than those on the west coast throughout life. Although B. frenchii spawns daily during the main spawning season, which extends from October to February on both coasts, its fecundity at any given length is substantially greater on the south than on the west coast. The more rapid growth of juveniles and earlier attainment of maturity by B. frenchii on the south coast than on the warmer west coast, together with maturation at a similar size on both coasts, run counter to the trends observed in many species and certain ecological theories regarding the relationships between life-cycle traits and latitude and temperature. The attainment by B. frenchii of a larger body length at age, of greater body mass at length and of greater fecundity at both length and body mass in fish on the south than on the west coast strongly suggests that conditions on the former, cooler coast are more favourable for this labrid, which belongs to a sub-genus whose other species typically live in cool, deep, temperate waters. [source] Sexual development and reproductive seasonality of hogfish (Labridae: Lachnolaimus maximus), an hermaphroditic reef fishJOURNAL OF FISH BIOLOGY, Issue 5 2007R. S. McBride The seasonality, size, age, colour phases and sexual dimorphism of 13 reproductive classes of hogfish Lachnolaimus maximus are described. Analysis of histological sections of gonads (n = 1662) confirmed earlier conclusions that L. maximus is a monandric, protogynous hermaphrodite. Sex change was initiated at the end of the spawning season and over a broad range of sizes and ages. It occurred after a functional female phase (postmaturation) and proceeded more slowly (months) than previously believed. Eventually all individuals changed sex to a terminal male phase. Females were batch spawners, spawning as often as every day during winter and spring. There was no evidence of precocious sperm crypts in active females, sperm competition or other alternative male sexual strategies. Mating has been reported elsewhere to be haremic. The sexual development of L. maximus appears to be adaptive in terms of Ghiselin's size-advantage model, which links monandric protogyny and polygyny. The slow rate of sex change, however, poses problems when fishing pressure is high because harvest of a single male has the potential to reduce the reproductive output of an entire harem. [source] Reproductive cycle and sex inversion in razor fish, a protogynous labrid in the southern Mediterranean SeaJOURNAL OF FISH BIOLOGY, Issue 6 2004G. Candi The reproductive biology of the Mediterranean razor fish Xyrichthys novacula was investigated by demographic data and histological analysis of the female, intersexual and male gonads. Specimens were collected by bottom trawl on a monthly basis between June 2000 and July 2001 in a sandy bay in southern Thyrrenian. Gonad histology confirmed that the Mediterranean razor fish is a monandric, protogynous hermaphrodite. Females reached first sexual maturity at 100 mm (LT) and the estimated mean LT at first maturity (L50) was 125 mm. Females exhibited asynchronous ovarian development and multiple ovulations occurred over the spawning period. Vitellogenesis started in early May and spawning occurred from late May until late September. Sexual transition involved a large-scale atresia of all oocyte stages and a massive degeneration of ovarian tissue followed by primordial germ cells proliferation. Sex change began at spawning time (June) but transitional individuals tended to cluster at the end of the reproductive period (September). They accounted for 17·1% of the population sampled and were found in a broad size range (105,150 mm LT). [source] Gonad development and evidence of protogyny in the red-throat emperor on the Great Barrier ReefJOURNAL OF FISH BIOLOGY, Issue 2 2003K. Bean The gonad development in the red-throat emperor Lethrinus miniatus is described and the first detailed evidence for protogyny in this species provided. The identification of transitional individuals, bimodal sex-specific size-frequency distributions and female biased sex ratios suggest that L. miniatus is most likely a protogynous hermaphrodite. Transitional L. miniatus gonads were characterized by the concurrent degeneration of all oocytes and the proliferation of spermatocysts near the edge of the lamellae, an increase in blood vessels along strands of stromal tissue within the lamellae and the formation of multiple sperm sinuses. The sites of oocyte degeneration and proliferation of spermatocysts were spatially segregated. An increase in blood vessels along strands of stromal tissue within the lamellae of transitional phase gonads is likely to assist in the breakdown of oocytes and the proliferation of spermatocysts. Most mature resting females containing spermatocysts occurred within the transitional size-frequency distribution, suggesting that the presence of spermatocysts in these females may be an early sign of sex change. Oocytes within female gonads were interrupted by filamentous strands of stromal tissue within the lamellae. The testis contained a remanent ovarian lumen but no residual oocytes. Three characteristics of transitional L. miniatus gonads were found to be unusual and described for few other species of coral reef fishes. These included the absence of oocytes within testes, increased numbers of blood vessels, and the presence of strands of stromal tissue within the lamellae. [source] The effects of temperature on sex differentiation and growth of black sea bass (Centropristis striata L.)AQUACULTURE RESEARCH, Issue 6 2009Heidi R Colburn Abstract To examine the effects of temperature on sex differentiation in the black sea bass (Centropristis striata L.), a protogynous hermaphrodite, juveniles (,0.5 g) were cultured in recirculating systems at 17, 21 or 25 °C. Growth was assessed at 155, 182, 241 and 275 days post hatch and sex differentiation was determined histologically. No differences were found in the sex ratios of fish reared at different temperatures, but only 55,64% developed as females. Growth was significantly greater in males across all temperature treatments. These results suggest that black sea bass exhibit sexually dimorphic growth patterns and that female-specific sex determination can be disrupted in culture. [source] | ||||||||||