Aspectos reprodutivos do peixe traíra, Hoplias malabaricus (Bloch, 1794) (Characiformes: Erythrinidae) no Açude Marechal Dutra, Rio Grande do Norte, Brasil

Abstract

This study verified the reproductive biology of a neotropical fish, Hoplias malabaricus (Bloch, 1794). Present study was conducted in the Marechal Dutra reservoir of Piranhas-Assu hydrographic basin, Rio Grande do Norte, Brazil. The fish were captured monthly from August, 2015 to June, 2016. Fish were identified taxonomically, weighed, measured and sex was identified. The following aspects were checked: total body length, total weight, sex ratio, type of growth, length of first sexual maturity (L 50 ), aspects of gonad development, condition factor (K) and gonadossomatic index (GSI). A total of 141 individuals of H. malabaricus were captured and the sex ratio was 1M: 1.4F. The total length of grouped sex varied from 12.7 cm to 41.5 cm (32.4 ± 7.0) and the total weight varied from 18.0 g to 1028.0 g (456.7 ± 230.1). The value of angular coefficient (θ) was 3.1552 for males and 3.0916 for females, indicating isometric growth. The value of L 50 was 32.6 ± 0.97 cm for males and 31.5± 0.77 cm for females. The gonad maturity stages observed were: immature, maturing, mature and spent. The GSI of grouped sex showed peaks in August (1.78 ± 1.96), December (3.87 ± 12.01), February (1.41 ± 1.58) and April (1.79 ± 2.72). There was a negative correlation between condition factor (K) and GSI (r = -0.7187; p > 0.05), thus suggesting the use of energy reserves during maturation and reproductive period. Based on the value of L 50 it is recommended that H. malabaricus should be captured above 32.6 cm of total body length, in order to conserve the fish stocks in the Marechal Dutra reservoir of Rio Grande do Norte, Brazil. Keywords: H. malabaricus ; gonadal development; sex ratio; length at first sexual maturation; gonadossomatic index.