The Effect of Potassium Concentration in Inland Saline Water on the Growth and Survival of the Western King Shrimp, Penaeus latisulcatus Kishinouye, 1896

Abstract

The survival, growth, and condition of the western king shrimp, Penaeus latisulcatuswere measured for 42 days when grown in marine water and inland saline water with four different concentrations of potassium: 100%, 80%, 60% or 40% of the concentration of potassium in marine water (IS100, IS80, IS60, and IS40). Shrimp survival and cannibalism frequency decreased with decreasing potassium concentration, with final shrimp survival in IS100 significantly higher (P < 0.05) than in IS60 and IS40 and significantly higher (P < 0.05) in MW and IS80 than in IS40. Specific growth rate (SGR), moult increment, and diet ingestion rate of shrimp were significantly higher (P < 0.05) in shrimp grown in marine water than the other water types. At the conclusion of the trial, exoskeleton mineral content of shrimp in IS100 and IS80 was significantly higher (P < 0.05) than in IS60 and IS40. Tail muscle moisture content of shrimp in IS60 and IS40 was significantly higher (P < 0.05) than in the other water types, suggesting a depletion of tail muscle energy reserves in IS60 and IS40. This trial demonstrates the necessity of fortifying potassium-deficient inland saline water to allow the culture of western king shrimp. Furthermore, a potassium concentration greater than approximately 76% of that in marine water and a Na/K ratio of less then 39 appear to be necessary to maintain a comparable level of shrimp survival, as in marine water. However, the slower growth and reduced molt increment of shrimp in inland saline water with 100% and 80% potassium compared to shrimp in marine water demonstrates the presence of other limiting factors.