Combined Effect of Salinity and Temperature on Oxygen Consumption and Metabolic Rate in Penaeus monodon Fabricius, 1798 (Decapoda, Penaeidae)

Experiments were carried out to investigate the effect of salinity on the oxygen consumption and metabolic rate of Penaeus monodon of varying body mass. In the present study, the shrimps were exposed to salinities from 0 to 45 ppt. The adults were not very comfortable with sudden increasing salinities at all the temperatures studied. The percentage increase in the metabolic rate of juvenile shrimp is about 37% at 25°C and 12% at 30°C with increasing salinity from 1 to 45 ppt. In the sub-adults, the percentage increase in metabolic rate further decreased with increasing salinity. The significant observation made at temperatures (15–20°C) is that there is not much variation in the oxygen consumption and metabolic rate with increasing salinities (10 ppt) and that the variation in metabolic rate is marginal. In further experiments, when the temperature was increased to 25°C, 30°C, and 35°C, minimal oxygen consumption rates were observed in freshwater (0 ppt) and at 5 ppt salinity. The effect size similar to R2 in the linear regression and the difference between the averages of all groups is to be statistically significant at 150 C. The F-value is 2.02 at 95% region of acceptance and the p-value is equals to 0.0499, the smaller the p-value is strong support to H1.