Influence of salinity on the size at maturity for fish species reproducing in contrasting West African estuaries

Jacques Panfili 1 Diaga Thior 2 Jean-Marc Ecoutin 3, 4 P. Ndiaye 5 Jean-Jacques Albaret 4
1 ECOLAG - Ecosystèmes lagunaires : organisation biologique et fonctionnement
2 IFAN
3 LEMAR - Laboratoire des Sciences de l'Environnement Marin (LEMAR)
4 IRD [Sénégal] - Institut de recherche pour le développement
5 IFAN
Abstract : The influence of salinity on life-history traits was tested using two adjoining West African estuaries: the Gambia with a 'normal' salinity gradient (salinity always <40 and decreasing from the mouth upstream) and the Sine Saloum (Senegal) with an inverse gradient (from 35 at the estuary mouth up to >130 in the upper reaches). The breeding seasons and subsequent fork length (LF) at first maturity (LF50) were estimated for different fish species reproducing both in the Sine Saloum and in the Gambia River estuaries using a database built from experimental fish samplings between 1990 and 2003 with a purse seine (30 locations in the Sine Saloum and 44 in the Gambia). The database contained 30 553 individuals belonging to 60 different species among which only 20 species reproduced in both estuaries. The breeding seasons peaked just before, or at the beginning of the rainy season (June to July), and there were almost no sexually mature fishes at the beginning of the dry season (November to December). Patterns of differences between LF50 of the two estuaries did not follow a general trend (positive or negative), but varied in the same way for females and males of a given species. The LF50 was only systematically reduced with increasing salinity in species living in high-salinity waters (>70). For species living below 70, differences in sizes at first maturity between the two estuaries did not show any clear relationship with salinity. The smallest mature individual found in an environment was a good indicator of the size at first maturity reached in a particular ecosystem because the trend of the species differences between the two ecosystems generally followed that of the differences in size at maturity.
Keywords : adaptive response Gambia estuary life-history traits sexual maturity Sine Saloum estuary
Type de document :
Article dans une revue
Journal of Fish Biology, Wiley, 2006, 69 (1), pp.95-113. 〈10.1111/j.1095-8649.2006.01069.x〉
Liste complète des métadonnées
http://hal.univ-brest.fr/hal-00651221
Contributeur : Catherine Bertignac <>
Soumis le : mardi 13 décembre 2011 - 10:26:26
Dernière modification le : jeudi 11 janvier 2018 - 06:22:24

Lien texte intégral

istex

Identifiants

Collections

IUEM | UNIV-BREST | LEMAR | THESES_IUEM | AGROPOLIS | CMM

Citation

Jacques Panfili, Diaga Thior, Jean-Marc Ecoutin, P. Ndiaye, Jean-Jacques Albaret. Influence of salinity on the size at maturity for fish species reproducing in contrasting West African estuaries. Journal of Fish Biology, Wiley, 2006, 69 (1), pp.95-113. 〈10.1111/j.1095-8649.2006.01069.x〉. 〈hal-00651221〉

Exporter

BibTeX TEI DC DCterms EndNote

Partager

Métriques

Consultations de la notice

162

Contact

support.ccsd.cnrs.fr
hal.support@ccsd.cnrs.fr
Logo CCSD