Reproductive biology of the Caribbean sharpnose shark, Rhizoprionodon porosus, from northern Brazil
Mattos, S.M.G.; Broadhurst, M.; Hazin, F.H.V.; Jonnes, D.M. (2001). Reproductive biology of the Caribbean sharpnose shark, Rhizoprionodon porosus, from northern Brazil. Mar. Freshw. Res. 52(5): 745. https://dx.doi.org/10.1071/mf00113
In: Marine and Freshwater Research. CSIRO: East Melbourne. ISSN 1323-1650; e-ISSN 1448-6059, meer
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| Trefwoorden |
Growth period > Developmental stages > Maturation period
Life history
Elasmobranchii [WoRMS]; Rhizoprionodon porosus (Poey, 1861) [WoRMS]
Marien/Kust |
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| Auteurs | | Top |
- Mattos, S.M.G.
- Broadhurst, M.
- Hazin, F.H.V.
- Jonnes, D.M.
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| Abstract |
sharks,Rhizoprionodon porosus, were collected fromcatches of vessels fishing with gill-nets off the coast of northern Brazilbetween April 1996 and July 1997. The total sex ratio post partum was significantly biased towards females (1:1.57), but significantly more immature males than immature females were sampled (1.45:1), indicating sexual segregation. Females and males were categorized into reproductive stages according to changes in their reproductive tract. Size at sexual maturity for females was estimated to be ˜65 cm total length (TL), and males matured at between ˜65 and 70 cm TL. Gravid females had 1 to 8 embryos that approached a size at parturition of between ˜33 and 37 cm TL. The sex ratio of embryos was significantly biased towards females (1:1.79). Positive linear relationships were detected between TL of mature females and ovarian and uterine fecundities. Concurrent ovulation and gestation cycles and a clear relationship between embryonic development and maturation of the ovary showed that females are ready to copulate immediately after parturition. Reproduction occurs annually ,and although a peak in copulation was detected between late winter and early summer, many females appear capable of mating at any time throughout the year. |
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