Effect of thermal stress on Haemoglobin concentration of Indian major carp Catla catla (Hamilton)

Abstract

To differentiate thermal-stress (het-stress and cold-stress) from thermal-adaptation with in the fishes Catla catla were readapted to an abrupt rise of temperature from 22 ⁰c to 32⁰c at the rate of 1⁰c ̷ hour (heat-stress) and to a slow rise of temperature at the rate of 1⁰c ̷ 60 hours (heat-adaptation). In haemoglobin content the heat-adapted fish exhibited a gradual elevation and the cold-adapted fishes exhibited a gradual decrease. However the %recovery is higher during heat-adaptation than that of cold-adaptation. On the other hand the stressed fish heat as well as cold exhibited initially fluctuations in haemoglobin content. The per cent recovery in stressed fishes is relatively much lower when compared to the thermal- adaptation. Studies of this nature are highly useful in evaluating methods for the safe rearing and conservation of economically important Ichthyofauna of the aquatic habitat.