Excessive Manure Impact on Rohu Mortality in Aquaculture

The intensification of freshwater aquaculture has increased the use of organic manures such as cow dung and poultry litter in carp culture, especially for Rohu (Labeo rohita). While moderate application enhances plankton production and supports natural food webs, excessive usage has become a major cause of water quality deterioration and fish mortality. This study evaluates the mechanisms by which excessive organic loading affects Rohu, including oxygen depletion, ammonia toxicity, algal blooms, pathogen proliferation, sediment accumulation, and heavy metal contamination. In addition, the economic and nutritional importance of Rohu, the comparative roles of cow dung and poultry litter, and the socio-economic dimensions of farmer costs and government extension services are discussed. The findings emphasize that balanced manure application, coupled with sustainable management practices, is essential to reduce mortality and improve ecological and economic stability in freshwater aquaculture.