Effect of temperature on growth performance of red tilapia (oreochromis spp.) fingerlings

Abstract

This study evaluated the thermal tolerance and the effects of increased water temperature on the growth performance and survival of red tilapia (Oreochromis spp.) fingerlings. Two experiments were carried out. In the first experiment of thermal tolerance determination, water temperature was quickly increase and decrease to determine critical thermal minimum (CTmin), lethal thermal minimum (LTmin), critical thermal maximum (CTmax), and lethal thermal maximum (LTmax) of acclimated fish from three different temperature groups (28C, 31oC, 34oC). There were no significant changes regarding CTmin, LTmin, CTmax, and LTmax (P>0.05). Loss of equilibrium occurred at 12.13oC-12.63oC for cold temperature and 40.67oC-41.20oC in warm temperature; and death occurred at 9.77oC-10.27oC for cold temperature and 42.33oC-43oC in warm temperature. However, it was interestingly temperature acclimation strongly affected the time of tolerance of red tilapia (P<0.05). The higher the acclimated temperature, the longer they could tolerate to cold water, and the shorter they could withstand the warm water. In the second experiment, two acclimated fish groups (31oC and 34oC) and one control group (28C) were cultured for 50 days for comparing growth performance and survival. The weight gain and specific growth rate (SGR) of fish at higher temperature (31C and 34C) were significantly improved (P<0.05), while only 31C treatment gave a significant lower feed conversion ratio (3.41 compared with 4.71 and 4.14) (FCR) (P<0.05). However, there were no significant differences regarding net weight gain (P>0.05). Similarly, survival rate of the treatments and the control group were not significantly different (P>0.05). This study revealed an interesting view to the thermal tolerance pattern and effects on growth performance of red tilapia in the context of climate change and increase in water temperature. Keywords: Red tilapia, climate change, heating, upper tolerance, lower tolerance, growth performance