Observations and techniques for maturation, spawning, and larval rearing of the yellowtail snapper Ocyurus chrysurus

This paper describes current techniques used at our laboratory for the cont rolled spawning, maturation and larval rearing of the yellowtail snapper. J uvenile yellowtail snapper were obtained from Florida and transferred to th e Fisheries and Mariculture Laboratory in July 1990. Temperature and photop eriod manipulation resulted in precocial spawning in 1991, with sustained s uccessive spawning beginning in February 1992. Average weekly spawning from 1992-1994 was 308,000 and 247,000 eggs/tank, with fertilization rates of 4 6.1% and 32.5% for fish maintained in two separate spawning tanks. Observat ions on spawning activity from 1995 to 1996, during which a decreasing tren d in egg and larval quality was observed, imply a possible problem with bro odstock nutrition. Evaluation of feeding regimes during this period indicat ed a shift to a high (almost exclusively) usage of fresh squid and a reduct ion in fish and shrimp. Returning to a feeding regime of alternating feedin gs of fresh fish, squid, and shrimp have yielded improved spawning and egg quality. Larval rearing techniques using live and prepared feeds has result ed in an overall survival of 3% from egg to advanced juvenile. Grow-out of first generation (F1) juveniles yielded a marketable size (1 lb) fish in 25 mo. Spawning of F1 fish began in 1998, larval rearing and grow out of F2 f ish are currently underway. Results demonstrate that yellowtail snapper cul ture is technically feasible; however, further research to develop species specific culture techniques will be required before the culture potential o f this species can be accurately evaluated.