
TY  - JOUR
A1  - Mattos, Sergio M. G. 
A1  - Broadhurst, Matt 
A1  - Hazin, Fabio H. V. 
A1  - Jonnes, Danillo M. 
T1  - Reproductive biology of the Caribbean sharpnose shark, <emph type="2">Rhizoprionodon porosus</emph>, from northern Brazil
JF  - Marine and Freshwater Research
JO  - Mar. Freshwater Res.
Y1  - 2001
VL  - 52
IS  - 5
SP  - 745
EP  - 752
KW  - maturation, elasmobranch, life history
UR  - https://doi.org/10.1071/MF00113 
N2  - Two hundred and seventy three Caribbean sharpnose sharks,Rhizoprionodon porosus, were collected from catches of vessels fishing with gill-nets off the coast of northern Brazil between 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. 
ER  -

