Volume 62
Preliminary Results about the Age and Growth of the Caribbean Sharpnose Shark, Rhizoprionodon porosus (Poey, 1861), from the Northeastern Region of Venezuela
Authors
Medina, E,; Tavares, R,; Posada, J.M. Download PDF Open PDF in BrowserOther Information
Date: November, 2009
Pages: 441-445
Event: Proceedings of the Sixty -Second Annual Gulf and Caribbean Fisheries Institute
City: Cumaná
Country: Venezuela
Abstract
The present study describes the catch structure and growth biology of Rhizoprionodon porosus from the northeastern region of Venezuela, based on individuals caught by the artisanal fishery in Margarita Island (period 2008-2009). At the present time, a total of 286 individuals (33,5-97,7 cm TL) have been examined; of them, 53.5% were males and 46.5% were females. The newborn individuals (mean: 43.2 cm TL) were observed between January and April (2009), indicating the birth season in the study area. The analysis of sexual maturity for males was based in a total of 153 individuals, with an estimated mean length at maturity (TL50%) of 71.5 cm TL. For age determination, a total of 32 males (41.5-71.0 cm TL) and 18 females (33.5-68.9 cm TL) have been study, with the maximum estimated longevity on 9 years. The trend found in the variation of the analysis of marginal increment rate (MIR) suggests, at the time being, an annual periodicity for the ring formation. Asymptotic length individuals (~100 cm TL) must be incorporated into the analysis, so reasonable growth parameters can be estimated. This study represents an important contribution for the use of vertebrae on age and growth studies of sharks in tropical areas.