Composite fish culture has emerged as a vital activity in recent years owing to high net return realized from this enterprise.
Nevertheless, there still exists a large gap in the demand and supply of fish. Intensive aquaculture is not feasible for the rural people as it is expensive and involves more risk.
The low input mixed farming systems in which fish culture is a component, using and regenerating the physical and biological resources efficiently, are more suitable as they are less risky and at the same time give more fish production because of easy adaptability.
The current aquaculture production can be increased to a greater extent if it can be integrated with dairy. Fish cum dairy farming is considered as an excellent innovation for effective utilization of organic wastes.
Composite fish culture comprising rohu, catla, mrigal and common carp can be fed with biogas slurry, cattle shed washings and other organic wastes for reducing the cost of feeding and to improve the growth and yield. Organic wastes on application help in the production of desired planktons, which is basic food for fish and these wastes serve as fertilizer nutrients and also consumed directly as source of feed.
Experiments conducted at Tamil Nadu Agricultural University, Coimbatore revealed that application of biogas slurry from the biogas plant at 15,000 kg ha of fish pond and cattle shed washings at 260 litres day-1 for 73 days as fish feed recorded 40.45 kg and 45.92 kg, respectively .
Feeding the fish with improved nutrient feed especially organic carbon and plankton status of fish pond, resulted in highest productivity.
Excess supply of cattle shed washings to fish pond resulted in mortality of fish due to high water temperature, carbon dioxide, alkalinity and low dissolved oxygen content of water in the fish pond.
Hence, for obtaining higher fish production and economic returns, growing of polyculture fish with cattle shed washings or biogas slurry as their feed is efficient and economical.
Krishi Vigyan KendraVirinjipuramVellore, Tamil Nadu Agricultural University