Effects of increasing water temperature and decreasing water oxygen concentration on enzyme activity in developing carp embryos (Cyprinus carpio)
Climate change inevitably leads to increased water temperatures, which is especially important in natural spawning grounds during mass fish spawning. Studies were performed to determine the effects of increased water temperature with decreased water oxygen concentrations on the activity of Na+/K+ ATPase, lactate dehydrogenase (LDH), and succinate dehydrogenase in developing carp embryos. The activities of ATP and LDH decreased several times when water temperature increased from 24 to 31°C. LDH activity increased up to 1.9 times. Thus, the fish embryos used glycolysis to a greater extent, the level of their aerobic respiration decreased, and mineral exchange with the environment was weakened. These phenomena could have disrupted embryonic development and decreased fish embryo viability.