Formação e manejo de um plantel de reprodutores do beijupirá (Rachycentron canadum) em Pernambuco

Abstract

Cobia (Rachycentron canadum) is a neritic and epipelagic fish that presents an active behavior due to the lack of gas bladder. It is naturally found in tropical and subtropical waters of every ocean, except the eastern Pacific. Due to its high growth rate, good commercial value and fine quality meat, it has a great potential for farming. With this in mind, the Department of Fisheries and Aquaculture, Universidade Federal Rural de Pernambuco (UFRPE), in association with Aqualider Maricultura Ltda., initiated a joint research effort aiming to form a breeding stock based on the capture of wild specimen. Fish were placed in tanks with constant water renewal and/or pure oxygen, and transported to the laboratory (70 km away). Upon arrival at the lab, fish were anesthetized with clove oil (15 to 20 ppm), tagged and their sex was determined through the insertion of a 1 mm cannula. Fish were also bathed in a formaldehyde solution (100 ppt for 30 min) and freshwater (maximum 5 min) against external parasites. Twenty nine fish were captured, from which only seven survived. Deaths were more frequent at the beginning of the study. As tanks were covered and the team acquired more experience, especially in the acclimation procedures and treatment of parasites, a substantial decreased in deaths resulted. Although at the end of the acclimation process the number of breeders was reduced to seven (two females with mean weight of 14-16 kg, four males with around 10 kg each and a specimen with unknown sex), these animals produced 21 fertilized spawns, which resulted in a total of 48.7 million eggs, from which 24 million were fertilized (mean fertilization of 49.3%). Compared to similar attempts to breed wild cobia in captivity, the present results may be considered excellent. It was therefore demonstrated the viability of the methodology employed here in the formation and management of a cobia breeding stock.