Nursery Culture of Grouper (Epinephelus fuscoguttatus Forsskal) and Sea Bass (Lates calcarifer Bloch) in Brackish Water Ponds: Co-Feeding of Zooplankton and Formulated Diets Containing L-Tryptophan

Abstract

This study compared co-feeding zooplankton (ZP, mixed copepods and mysids) and formulated diets (FD) supplemented with L-tryptophan (TRP) on the survival and growth of grouper and sea bass fry nursed in brackish water ponds. Grouper (84 fry m⁻³) and sea bass (150 fry m⁻³) were reared for 30 days and 60 days, respectively, in net cages within two separate 743 m² nursery ponds. Five treatments (with three replicates each) were compared (P < 0.05): FD-1 = ZP + basal FD (no added TRP, but containing 0.29% endogenous TRP); FD-2 = ZP + (FD 0.58% TRP); FD-3 = ZP + (FD 1.22% TRP); FD-4 = ZP + (FD 2.50% TRP); and FD-5 = minced fish (Sardinella sp.) + basal FD (no additional TRP). TRP supplementation in grouper diets produced no significant affect on growth but increased survival at rates of 0.58% and above. TRP supplementation at 2.5% (FD-4) produced significantly better sea bass growth than other diets but had no affect on survival. Zooplankton improved both survival and growth in both grouper and sea bass juveniles compared to the minced fish diet, and may be a practical and lower cost alternative to indoor nursing.

Keywords:

• Fish fry
• net cage culture
• copepods
• mysids
• artificial diet

Acknowledgments

We gratefully appreciate Messrs. Jupit Donoso and Gene Javero for their technical assistance, Mr. Daniel Reyes for the water quality analyses, Ms. Gwen Anuevo for the proximate analyses of samples, and Mr. Gerald Gonzaga and other feed mill staff for the feed preparation. Thanks are due to Dr. Mae Catacutan and Dr. Teodora Bagarinao for reviewing the earlier draft and to the anonymous referees for their constructive comments on the final version of the manuscript. This study was supported by SEAFDEC/AQD under the Budget Code 5303-T-TV-F0608D.