Estimativa da abundância relativa de corvina na costa centro-sul do Brasil

Abstract

SYNOPSISThe aim of this paper is to evaluate the apparent abundance of the croaker (Micrapogon furnieri) along the central and southern coast of Brazil (from 23°50'S to 35°S). The data on catch 'and effort of the fish taken in the same area and at the same time, with different gear, are analysed from January 1959 to December 1962.The different gears used were reduced to the same leveI of efficiency, and the apparent abundance was estimated according to the fishing area (area I -from 23°50'S to 26°S, and area II -from 26°S to 35°S) , by quarters and by year.The results allow us to draw the following conclusions: 1 -There is a tendency of increase of the apparent abundance from the beginning to the end of each year and of decrease in following years, in Doth areas. The decrease is greater in area II.2 -The leveIs of apparent abundance, in both areas, was very · different. The leveI in area II is higher.3 -Variations in the availability during the year, were observed. Data suggest that they are determined in area I by extrinsic factors, and in area II by intrinsic factors.4 -Different responses of the stock, in both areas, to fishing intensity was verified, supporting the hypothesis of occurrence of two different croaker stocks. The stock of area I probably has reached a state of equilibrium with the fishery while in area II the stock has not yet reached this stage. INTRODUÇÁONa estimativa da densidade de uma população natural, a pesca comercial pode ser considerada como uma fonte de amostragem dessa população, sendo que a produção por unidade de esfôrço reflete, até certo ponto, as variações da densidade relativa.A densidade e abundância relativas de uma população natural estão relacionadas com as verdadeiras densidade e abundância, pela disponibilidade.•• Os dados utilizados na preparação dês te trabalho foram cedidos pelo "Grupo de Pesquisas sôbre a Pesca lVIarlt1ma", a quem agradecemos. Publ. no 203 do Inst. Oceano da USP.