Idade e crescimento da pescada amarela, Cynoscion acoupa (Lacepède, 1801) (Perciformes, Sciaenidae), capturada no litoral ocidental do Maranhão, Brasil

Abstract

The acoupa weakfish (Cynoscion acoupa) is a medium to large fish, marine estuaries, distributed in the Atlantic from Panama to Argentina. It is very common in the north coast of Brazil, highlighting the states of Pará and Maranhão. The present study aimed at compiling biology and fisheries information of the species, as well as estimating age and growth, population structure and mortality of C. acoupa in the north coast of Brazil. The data showed that C. acoupa fishery occurs during every month of the year, however, with sharp declines in species landings in recent years. For age and growth analysis, we used 255 specimens of acoupa weakfish, in the rigid structure method, the otoliths were used, in which the formation of one ring per year were verified, when testing growth models, contacting von Bertalanffy's model the best, resulting in the parameters k = 0,13, L∞ = 142,95 cm and t0 = -0,45 years old and there was no difference in growth between the sexes. Already by distribution of class method the length resulted in k = 0,28, L∞ = 112,6 cm and t0 = -0,41 years old. These data indicated a slow growth and long life cycle for the species. The population structure of C. acoupa in Maranhão is composed of a balance between males and females, with 54% of the captured population being young individuals, who are less than 2.4 years old. The total mortality rates estimated for C. acoupa, in Maranhão, indicated a value of Z = 1,04 year¹ for individuals caught near the coast and Z = 0,60 year¹ for specimens more distant from the coast, a population overexploitation (E = 0,61), especially on young individuals, which are caught in high quantity almost every month, with the exception of the winter season, when the adults number captured is higher. Excessive capture of young specimens may be causing a decrease in reproductive stocks, and consequently, a decrease in the number of new recruits in the population, which are not sufficient to cover the mortality caused by fisheries. For this reason, the population decline due to overexploitation and biological vulnerability may be pointing to a critical situation of the species, being urgently necessary to take measures aimed at the sustainable management and conservation of the species in the north coast of Brazil.