Thermal tolerance and oxygen consumption of Labeo rohita and Cyprinus carpio early fingerlings acclimated to three different temperatures

Abstract

To compare the species-specific variation in thermal tolerance and metabolic activity, critical thermal maximum (CTMax), critical thermal minimum (CTMin), lethal thermal maximum (LTMax), lethal thermal minimum (LTMin) and oxygen consumption rate of Labeo rohita and Cyprinus carpio early fingerlings were determined after acclimating at 25°C, 30°C and 35°C for 30 days. CTMax (40.2±0.04, 41.6±0.08, 42.2±0.11); CTMin (12.9±0.04, 14.2±0.04, 15.0±0.05); LTMax (40.4±0.05, 41.9±0.09, 42.7±0.05); LTMin (11.5±0.03, 13.5±0.05, 14.4±0.04) increased significantly ( p<0.05) in L. rohita with increasing acclimation temperatures . Similarly, CTMax (39.7 ±0.31, 40.6±0.07, 42.9±0.10); CTMin (8.4±0.04, 8.6±0.04, 10.2±0.09); LTMax (39.8±0.06, 40.9±0.07, 42.9±0.04); LTMin (8.2±0.05, 8.4±0.04, 10.1±0.05) increased significantly ( p<0.05) in C. carpio with increasing acclimation temperatures. Inter-species specific-variation (between L. rohita and C. carpio) was evident at 30°C and 35°C. Oxygen consumption rate increased significantly ( p<0.05) with increasing temperatures in both the species. However, temperature quotient ( Q 10) was more in L. rohita (1.61), in comparison to C. carpio (1.53). Overall results suggest that C. carpio is more thermal-tolerant and show better adaptation in comparison to L. rohita.