Reproductive biology of four-eyes fish, Anableps anableps, in São Marcos bay, Maranhão, Brazil

Abstract

The viviparous species Anableps anableps (four-eyes fish) is considered an important component of estuaries located on Maranhão coast due to its high representativeness and constancy. The present study aimed to describe the reproductive biology of A. anableps in São Marcos Bay, Maranhão. From May 2007 to April 2008, 267 specimens of four-eyes fish were caught, being 214 (80.1%) females and 53 (19.9%) males. The total length (TL) and total weight ranged, respectively, from 11.7 to 21.6 cm and from 16.8 g to 82.3 g for males; and from 13.5 to 28.2 cm and from 18.4 g to 200.0 g for females. The length-weight relationship did not differ between sexes, characterized as a species of negative allometry. The length of first maturity was 13.8 cm for males and 13.9 cm for females. The average fecundity of A. anableps was 12.9 embryos/pregnancy; higher number of embryos was observed when females had from 18.1 to 25.5 cm of total length. The spawning occurred during all year, with peaks in May and September. Seven stages of development were identified to this species, the last one when the embryos are ready to born, coinciding with the reproductive peaks of females.