ON-FARM EVALUATION OF AN ALTERNATIVE SALT MIXTURE FOR SALINITY ACCLIMATION OF PACIFIC WHITE SHRIMP Litopenaeus vannamei

Pacific white shrimp, Litopenaeus vannamei exhibit a remarkable ability to tolerate a wide range of salinities. However, proper acclimation to an appropriate environment is critical to ensure good survival. In the case of low salinity culture, post larvae are often transferred into systems for which the salinity has been adjusted with reconstituted sea salt (RSS), which are formulated for salt-water aquariums. However, the price is not within a sustainable range considering the volume of salt necessary for the acclimation process. Therefore, during the current study, a Low-cost salt mixture (LCSM) constituting sodium, potassium, calcium, and magnesium concentrations of 298, 9, 17, and 39 mg/L respectively in 1-g/L solution was prepared, which is comparable closely with the major cations in 1-g/L dilute seawater. Following several successful laboratory studies, the current study was conducted to evaluate the efficacy of LCSM to replace RSS under actual farm conditions. Experimental trials were carried out in two on-levee tank systems installed adjacent to a shrimp production ponds on a commercial farm in west Alabama. Each tank system consisted of 12, 800-L tanks supplied continuously with low salinity pond water via a regulated water pump. Upon arrival from the hatchery (at 32 g/L salinity), 100 shrimp post larvae (0.009±0.02g) were stocked into each tank with different ionic solutions (LCSM 0, 50, 75 and 100 %) at 30 g/L salinity. Salinity acclimation was done within 2-3 days by controlling the inflow to the tank to reduce the tank salinity from 30 g/L to 6 or 1.5 g/L. Following the acclimation, one tank system-maintained flow-through with the adjacent pond (1.5 g/L) while the other maintained static at 6 g/L by ceasing water circulation. Shrimps were fed six times during the day ad-libitum for 21 days. According to the statistical analysis, no significant differences were observed in survival and growth between different ionic solutions in both experimental systems. Outcomes of the current study revealed the potential of LCSM as an excellent source for acclimation of shrimp post larvae in practical farm conditions to bring down the cost of production in low salinity shrimp farming.