Culture of cobia (Rachycentron canadum): cryopreservation of sperm and induced spawning

Studies toward the development of cobia ( Rachycentron canadum ) aquaculture were initiated. Methods of cryopreserving cobia sperm were compared and sperm motility was assessed after longterm frozen storage. Sperm stored in 10% dimethyl sulfoxide, 3 mM glucose, and 10% raw chicken egg yolk showed approximately 100% motility upon thawing after more than 1 year of storage at −80°C. Sperm motility declined after about 60 min at room temperature, but approximately 100% motility could be restored by addition of a few drops of 5 mM theophylline. Ripe, wild-caught female cobia were held in recirculating seawater systems and ovulation was induced by injection of human chorionic gonadotropin at a concentration of 275 IU/kg of body weight. Fertilization was attempted using the cryopreserved sperm. Although fertilization did not occur, we are optimistic that cobia aquaculture is feasible.