Estimação de parâmetros de crescimento das espécies de peixe Lethrinus variegatus, Leptoscarus vaigiensis e Scarus ghobban, na região de Inhassoro, Província de Inhambane baseado em análises de frequências de comprimentos

Abstract

Within the framework of the Artisanal Fisheries Research Programme, length information obtained regularly through the National Artisanal Fisheries Sampling System in the period 1999-2007 was analysed in order to estimate the von Bertalanffy growth parameters for the fish species Lethrinus variegatus, Leptoscarus vaigiensis and Scarus vaigiensis in the Inhassoro District, Inhambane Province, Mozambique. Previously, an exploratory data analysis was carried out in order to determine the representativity of the various fishing gears in the total number of individuals of each species sampled annually, quantify the number of individuals measured monthly, and record the minimum and maximum lengths observed over time. Parameter estimation was carried out based on the analysis of monthly frequency distributions of one centimetre total length (LT), without separation of sexes, resulting from the aggregation of the samples available in each month. No differences were observed in the growth of the cohorts of each species present over the years so that only one set of parameters was adopted for each species. The value of the asymptotic length (Linf) was fixed based on the maximum dimensions of the individuals present in the samples of the two areas and the growth coefficient (k), compatible with Linf, was estimated using the ELEFAN I method, implemented in the statistical package FiSAT distributed by FAO. The estimated growth parameters for the three species were as follows: L. variegatus - Linf = 30.53 cm LT, k = 0.46 year'1; L. vaigiensis - Linf = 30.53 cm LT, k = 0.46 year*1 and £ ghobban - Linf- 95.78 cm LT, k = 0.31 year'1.(TRADUÇAO NOSSA)