Article

Population structure of the sicklefin lemon shark Negaprion acutidens within the Curieuse Marine National Park, Seychelles

Published in: African Journal of Marine Science
Volume 39, issue 2, 2017, pages: 225–232
DOI: 10.2989/1814232X.2017.1333453
Author(s): RD HodgkissGlobal Vision International Seychelles, Seychelles, A GrantGlobal Vision International Seychelles, Seychelles, JHR McClellandGlobal Vision International Seychelles, Seychelles, R QuatreSeychelles National Parks Authority, Seychelles, B RademakersGlobal Vision International Seychelles, Seychelles, C SanchezNature Seychelles, Seychelles, C Mason-ParkerGlobal Vision International Seychelles, Seychelles

Abstract

This study produced the first data on population parameters for sicklefin lemon shark Negaprion acutidens at the granitic Seychelles Islands, adding to a limited catalogue of species information. Juveniles at a site in the Curieuse Marine National Park were tagged over two periods, in 2014–2015 and 2015–2016, with measurements of length (precaudal, fork and total) and weight, sex, and state of the umbilical opening recorded. Recapture data were used to calculate growth rates and population size. Mean annual growth rate was 5.40 cm y–1. A mean size at birth of 62.5 cm TL is in line with previous assessments of the species. Population-size estimates were similar for the two sampling periods (comprising 311 and 255 individuals) and higher than anticipated. Movements to outside the lagoon were recorded for early ages, and this, combined with weight loss and a reduction in condition factor as displayed in several individuals, suggests that the study area alone could not support the large number of sharks pupped yearly.

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