Reproductive biology of Hassar affinis (Pisces: Siluriformes, Doradidae), Lake of Viana, Baixada Maranhense, Maranhão Brazil

ABSTRACT

The study of reproductive biology is important to determine protective measures for the maintenance of fish stocks. Thus, this study aimed to determine some aspects of the reproductive biology of Hassar affinis in the Lake of Viana, at the Baixada Maranhense, Maranhão, Brazil. A total of 147 specimens were used in the study. They came from commercial fishing, collected in the period between February 2012 and January 2013. In the laboratory, they were weighed and body traits measured. A longitudinal incision was made ventrally in order to macroscopically observe the gonads. After that, they were fixed in Bouin solution for microscopic analysis and Gilson solution for analysis of fertility. Negative allometry was recorded for both genders, indicating greater increase in length than by weight. The sex ratio for the entire period was 3.4 females per 1 male. There was a greater reproductive activity in the bimesters February/March and April/May, which indicates that the reproductive period of this species occur in these months. The average absolute fecundity is estimated in 47,211 oocytes. The first sexual maturity is reached at 11.52 cm. Based on these data, management measures are suggested, defining the reproductive for this species from February to May, and setting minimum catching size of 11.5 cm and, furthermore, it is suggested the development of other work at monthly intervals.

KEYWORDS:
Conservation; Fish; Neotropical region