Populational biology of brazilian mojarra Eugerres brasilianus (Cuvier, 1830) next to the São Francisco River mouth (Brazil)

Abstract

Eugerres brasilianus is one of the main marketable species in Northeastern Brazil and in the lower São Francisco River. The objective of this study was to evaluate the population structure of this species in the region. Fish were collected monthly through gillnet from May to December 2013. About 80% of the 95 individuals captured were females with standard length ranging between the classes 17.0 and- 29.0 cm. The weight/length ratio in females and males during the rainy and dry seasons presented a negative allometric type of growth. Gonadal maturation stages varied from B (under maturation) to C (mature) for females during the rainy season, indicating reproductive activity, a fact confirmed by the gonadosomatic index and the condition factor K, whose values were superior in females (p> 0.05). The results show that the species development may be related to the pre-reproductive period, because the growth in length was greater than in weight.