Early growth and juvenile population structure of lemon sharks Negaprion brevirostris in the Atol das Rocas Biological Reserve, off north‐east Brazil
Abstract:Lemon sharks Negaprion brevirostris were sampled in the Atol das Rocas, a nursery area, on nine occasions from March 1999 to October 2003, during which 157 individuals were tagged and 35 were recaptured. The male : female sex ratio of captured individuals was 1 : 1·12. Mean ± s.d. growth rates were 24·7 ± 3·4 cm year−1 in total length (LT), 20·7 ± 3·2 cm year−1 in fork length, and 19·5 ± 2·7 cm year−1 in precaudal length. There was no significant difference in growth rates between males and females. Mean ± s.d. increase in mass was 2565 ± 762 g year−1. The von Bertalanffy growth parameters estimated by the Fabens method based on LT were: k = 0·077, L∞ = 399·9 cm and t0 = −2·16. Despite the large variation of environmental conditions, particularly of tidal range and currents, and the lack of protective mangrove cover in the nursery area at Atol das Rocas, juvenile lemon sharks grew relatively faster than at other nurseries. Such rapid growth could be a response to abundant food availability or high risk of predation by adults that enter the nursery area.
Document Type: Regular Paper
Affiliations: 1: Departamento de Sistemática e Ecologia, CCEN, Universidade Federal da Paraíba, João Pessoa – PB, CEP: 58059-900, Brazil, 2: Bimini Biological Field Station and University of Miami, Rosensteil School of Marine and Atmospheric Science, Miami, FL 33149-1098, U.S.A. and 3: Department of Biological Sciences/University of Rhode Island, Kingston, RI 02881, U.S.A.
Publication date: 2006-05-01