Date of Award

1991

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Renewable Natural Resources

First Advisor

William R. Wolters

Abstract

Experiments with red drum, Sciaenops ocellatus, were conducted to assess environmental requirements and culture characteristics. Pond trials were used to evaluate the effects of salinity, chloride source, predator control, acclimation procedure, stocking density, and size at stocking on production. Survival in individual ponds ranged from 0-92%; average daily weight gain from 0.46-2.22g; and feed conversion ratio from 2.30-4.90. Survival, growth, and feed conversion ratio did not differ significantly between equivalent treatments in saltwater and freshwater ponds. The minimum chloride concentration necessary for acceptable production of red drum in freshwater ponds (250-300 mg/l) was at least 100% higher than the concentrations reported to support high survival and growth in some laboratory experiments. Mortality in ponds could be attributed to hypoxia, handling and stocking stresses, and vertebrate predators. A laboratory experiment was designed to determine the dissolved oxygen tolerance of juvenile red drum in relation to temperature and salinity. Fingerling red drum acclimated to combinations of 0.5 and 5 ppt salinity and 25 and 30 C survived to low dissolved oxygen concentration (0.34 mg/l) when concentration was reduced over several hours, as might occur in culture ponds. No difference due to temperature or salinity was detected in resistance to hypoxia. Red drum survived to significantly lower mean dissolved oxygen concentration when rate of deoxygenation was reduced. Results of these experiments indicate that red drum can be successfully cultured if water quality, predation, and handling stresses are controlled.

Pages

69

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