Haematological changes in the three Indian major carps, Catla catla (Hamilton), Labeo rohita (Hamilton) and Cirrhinus mrigala (Hamilton) exposed to acidic and alkaline water pH

The effect of water pH on certain haematological parameters was studied in the three species of Indian major carps, catla (Catla catla), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala) for 21 days by subjecting fingerlings of these fishes to acidic (pH 5.5, 6.5) and alkaline (pH 8.0, 8.5 and 9.0) water, control groups were maintained at neutral pH. A change in water pH either to acidic or alkaline conditions exerted stress in fish characterized by swelling of erythrocytes, production of immature erythrocytes, and reductions in the total erythrocyte counts, haemoglobin and serum protein content. There were also increases in total leukocyte counts and blood glucose. However, the degree of these responses varied among the three species. Rohu was found to be least affected followed by mrigal to the stress of altered water pH, while catla was the most vulnerable to pH changes.