Annual reproductive cycle of gafftopsail catfish, Bagre marinus (Ariidae) in a tropical coastal environment in the Gulf of Mexico

Abstract

Reproductive cycle of gafftopsail catfish (Bagre marinus) and its relation to environmental variables were analyzed, based on specimens collected randomly from commercial landings of long line artisan fleet of the Chiltepec Barrier, Tabasco State. Gonadosomatic index showed that this species had one reproductive period per year (May - August). Reproduction occurs in shallow coastal waters at high temperatures (27.0 - 29.0°C) under heavy precipitation conditions (170- 333 mm). Female condition factor had a similar behavior than the gonadosomatic index, reaching high values (0.61 to 0.63) during May through July, although a high value of 0.64 was observed during March. A decrease on the condition factor in males from July (0.55) to October (0.50) was related to the energetic cost of oral incubation. This finding was consistent with a decrease in the proportion of captured males during these months (from 50.7% in July to 23.9% in November) when males migrated from fishing areas to estuarine zones to release their progeny. Gafftopsail catfish presents a synchronic ovocitary development in two groups with total spawning. The species is characterized by low fecundity. The mean number of mature hydrated oocytes per female was 33, ranging from 21 to 62, which is related to the mouth brooding tactic wich allowed ariid species to survive under a variety of environmental conditions. Gafftopsail catfish take advantages of the different habitats present in its distribution area, by using a reproductive strategy with local seasonal migrations.