Some reproductive studies in Clarias batrachus with reference to different thermal conditions

Abstract

Eco-physiological study indicates the Clarias batrachus is a eurythermal fish and able to tolerate the wide range of climatic conditions. The quantitative analysis of nutritional components in gonadal region, such as glucose, proteins and fats showed the variations during exposure of fish to hot and cold temperatures. The fresh water catfish exhibits distinct phases of reproduction and also showed the changes in the levels of energy precursors with change in the excretory products, with respect to adaptability towards different environmental temperature conditions. Gradual increase of glucose, proteins, and cholesterol is observed in the male gonadal tissues. Rectal gland and clasper tissues showed, decreased of urea levels during the exposure of fish to the higher tolerable temperature. However, in female fish, the levels of proteins are significantly enhanced during the high temperature exposure. The levels of urea significantly decreased in the tissues of uterus and brain during the study period, while the lowering of glucose levels in brain indicates the extent of rate of physiological activity of the brain.