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 long-term 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-degrees-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.