Analysis of the variation of growth and mortality parameters of Sardines (Sardinella brasiliensis) from 1958 to 1978 Laura Simões Andrade, Antonio Olinto Ávila da Silva

Abstract

The Brazilian sardine is the most important fishery resource in Brazil, being the main species caught in the south and southeast. After declines in catches over the years, measures such as management plans for the sustainable use of the Brazilian sardine and closed seasons were created. This project was carried out in order to analyze the variations in the growth and mortality parameters of the Brazilian sardine (Sardinella brasiliensis) from 1958 to 1978. Data on the total length distribution of the Brazilian sardine unloaded in Santos, São Paulo, from August 1958 to December 1978, were recorded by the Fisheries Institute. The growth curve parameters were estimated by the nonparametric length frequency analysis method ELEFAN I, in the FISAT II program. The estimate of the total mortality rate and its confidence intervals were calculated by the linearized catch curve method based on lengths converted to age. The L∞ values ​​varied from 27.2 cm to 30 cm, and k values ​​varied from 0.49 to 0.63 year-1. The estimated Lmax value varied from 24.3 to 26.3 cm. The population parameters of the sardine varied little between the end of the 1950s and the mid-1970s, influenced by the increase in catches. The mortality rate (Z) varied from 3.24 to 6.09 year-1, being adequate to the variation in the fishing pattern of the time.