THE TECHNICAL FEASIBILITY OF POND LINERS FOR REARING PACIFIC WHITE SHRIMP (PENAEUS-VANNAMEI) IN TERMS OF SURVIVAL, GROWTH, WATER EXCHANGE-RATE AND EFFLUENT WATER-QUALITY

Three trials were conducted to investigate the technical feasibility of pond liners. The trials compared the survival and growth of the Pacific white shrimp, Penaeus vannamei, on plastic, sand and clay/mud substrates. The first 8-week trial, at the Texas Agricultural Experiment Station, showed no significant difference in survival among substrate treatments. There were, however, significant differences among final mean shrimp weights, at two salinities, in bare fiberglass tanks and tanks with sand or clay substrates. The final mean weights at 27 g kg-1 were 15.1 g, 14.2 g and 13.3 g, respectively. At 45 g kg-1 the final mean weights were 13.2 g, 11.9 g and 11.6 g, respectively. Subsequently, two 6-week rearing trials at The Oceanic Institute, Hawaii, compared shrimp survival and growth, water turnover rate and effluent water quality in liner, mud and sand substrate treatments. There were no significant differences in survival but, in both trials, mean harvest weights were significantly lower with the mud substrate than with the sand or liner substrates. Substrate type affected effluent water quality. Where Secchi disk depth was controlled, trials # 2 and # 3, water turnover was affected by substrate type in the following pattern mud> sand> liner. Significant differences were detected among substrate types in effluent concentrations of inorganic nutrients and total nutrients. The effluent stream sink accounted for 63% of total nitrogen and 65 of total phosphorus in the mud substrate treatment, and 70% of the total nitrogen and 97% of total phosphorus in the liner substrate treatment. Neither effluent pigment nor suspended material concentrations showed significant differences among treatments. These trials clearly demonstrated that pond liners are technically feasible in the culture of P. vannamei in the 1-16 g range and at densities from 15 to 50/M2.