Abstract— Age, Growth and Mortality of Tylochromis jentinki (Steindachner, 1895) in Ebrié Lagoon, Ivory Coast. Monthly data of length composition for Tylochromis jentinki (Steindachner, 1895), landed between February 2004 and January 2006 in Ebrié Lagoon (Ivory Coast) were used to estimate the growth, mortality and exploitation parameters of the stock. A total of 1850 individuals ranging from 7.5 to 23.5 cm SL (standard length), were examined. Length frequency data were analyzed with FiSAT software using the ELEFAN 1 package to estimate the population parameters. We estimated von Bertalanffy growth parameters: L∞ = 25.00 cm, K = 0.67 year-1, and t0 = -0.28 year-1, with the growth performance index, φ’ of 2.62. The length-weight relationship was W = 0.0215 x SL2.98 and described isometric growth for the species with an asymptotic weight (W∞) = 314.99 g. Total mortality (Z) estimated from catch-curve analyses was = 2.38 year-1. Natural mortality based on growth parameters and mean environmental temperature (T = 28ºC) was M = 1.45 year-1. Furthermore, the fishing mortality rate of 0.93 year-1 was by far in excess of the precautionary target (Fopt = 0.73 year-1) and slightly under the limit (Flimit = 0.97 year-1) biological reference points. With this level of mortality and exploitation level (E = 0.39 < 0.50), the stock was under-exploited.
Keywords— Age, growth, Cichlidae, exploitation, recruitment, length frequency.
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