Developing Hatchery and Growout Techniques for Bigeye Scad (Selar crumenophthalmus) Aquaculture

The results of a two-year research project designed to develop techniques for closed cycle production of bigeye scad (Selar crumenophthalmus) are described. Broodstock fish were captured approximately 5 nautical miles east-southeast of Key Biscayne Florida in waters 100 to 400 feet deep. A 28-ton, eight tank, recirculating aquaculture system (RAS) was designed, built and used for broodstock maturation and growout. Between June and October of 2009, thirty-six volitional spawning events were recorded during a five-month spawning season. A larval rearing protocol focused on modified greenwater techniques using microalgae (Isochrysis galbana and Nannochlopsis oculata) at total concentrations of 400,000 cells ml-1 and rotifers (Brachionus plicatilis) at densities of 30 to 50 rotifers ml-1 was developed. A larval rearing trial using this protocol produced 1,940 fully weaned, 45 dph fingerling bigeye scad with an average length of 38.8 ml and average weight of 1.3 g. Growout trials conducted from 45 dph to four and a half months post hatch were conducted. During growout trials fish were fed ad libitum twice a day using commercially available feed with 44% crude protein and 18% crude fat. Growout trials resulted in an average survival rate of 88%, absolute growth rates (AGR) of 28.23 to 30.26 g, and feed conversion ratios (FCRs) between 1.17 and 1.38. Results from an informal survey of local recreational fishing interests indicate that there is a large potential live-bait market for bigeye scad. Overall results from these trials show that bigeye scad aquaculture is technically feasible and suggests that the species is strong candidate for commercialization