Age, growth and mortality rates of round sardinella, Sardinella aurita (Valenciennes, 1810) from the Senegalese coasts (West Africa)

Abstract

Sardinella aurita is the main species exploited by small-scale fisheries in Senegal and represents an important source of low cost protein in the Senegalese market. The objective of this study was to determine the age, growth and mortality parameters of S. aurita obtained from the Senegalese coastal waters. Age, growth parameters and mortality rates of this species were estimated using FiSAT II (FAO–ICLARM Stock Assessment Tools) software. A total of 5104 specimens of S. aurita were collected monthly between March 2012 and February 2013 from commercial landings in three sites of Senegalese coasts (Joal, Mbour and Kayar). Mean growth parameters for the entire period were estimated as L∞= 32.82 cm, K= 1.10 year-1 and t0 = -0.14 year. Instantaneous total mortality (Z = 2.77 year-1) coefficients per year were estimated using catch curves and methods based on the mean length of the fish caught. Natural mortality (M = 1.49 year-1) was estimated using the Pauly’s empirical equation and fishing mortality (F = 1.28 year-1) by the difference between total and natural mortality values. The exploitation rate (E) of 0.46 indicated no over-fishing on this species. Key words: Round sardinella, age, growth, mortality, Senegalese coast.