Doctoral Dissertations

Date of Award

12-1990

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Ecology and Evolutionary Biology

Major Professor

J. Larry Wilson

Committee Members

Richard J. Strange, David A. Etnier, Don W. Byerly

Abstract

Water quality in intensive shrimp culture ponds was examined during one 5-month grow-out period. The measured parameters included temperature, salinity, Secchi disk transparency, pH, dissolved oxygen (DO) , biochemical oxygen demand (BOD), ammonia-N, nitrate, phosphate, total suspended solids, chlorophyll a, and plankton abundance/composition. Most water quality parameters changed relatively little over time except for specific trends in BOD, NH3, pH, and transparency. There were increases in levels of BOD (2.8 to 12.1 ppm) , and NH3 (0.0 to 1.5 ppm); pH decreased from 8.8 to 7.3 and transparency decreased from 80 to 40 cm. DO levels were relatively unchanged and maintained at 6-10 ppm over the grow-out period. Other parameters were considered as optimum levels for tiger shrimp culture, such as temperature (25-32 C) and salinity (20-32 ppt). BOD was identified as the most significant (P value < .05) parameter that affected shrimp feed efficiency; as BOD levels increased, feed efficiency decreased. During the grow-out period, the blue-green algae Oscillatoria sp. and the "pennate" diatoms were the dominant groups in the phytoplankton community while nauplius and rotifers were dominant in the zooplankton community. Phytoplankton densities and chlorophyll a concentrations increased as the grow-out proceeded. There were no significant effects of water exchange practices on the water quality parameters throughout the grow-out period.

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