Effect of Solar Radiation on Freshwater Fish Puntius bimaculatus (Bleeker) (Cypriniformes: Cyprinidae)

Environmental and physical stressors such as sunlight, atmospheric temperature, photoperiod, and UV radiation have a significant impact on all living organisms in the aquatic ecosystem, particularly on rocky shores, shallow water bodies, lakes, and ponds. In this study, the freshwater fish Punitus bimaculatus (Bleeker) (Cypriniformes: Cyprinidae) was exposed to solar radiation for 1h to 2h duration during the summer season from March to May (water temperature 40 ºC to 42 ºC). The stress caused by increased water temperature (40 oC to 42 oC) significantly reduced the physiological activities and alter the metabolism of the fish, particularly carbohydrate, protein, and lipid levels in the experimental fish, and also damaged the muscle tissue. The muscle carbohydrate, protein and lipid content of Punitus bimaculatus reduced when exposed at 40 ºC and 42 ºC . This could be due to the stress-induced on the fish to utilize the stored energy in the body. Punitus bimaculatus muscle tissue showed marked degeneration of the epithelium, disappearance of striations, and thickened septal wall. The continual degradation of primary metabolites is vital for tissue maintenance but is also important in allowing animals to adapt to changing environmental conditions, replace denatured or damaged proteins, mobilize amino acids, and allow metabolic regulation.