Livestock-fish system

Livestock-fish system includes cattle-fish system, pig-fish system, poultry-fish system, duck-fish system, goat-fish system, rabbit-fish system. In this practice, excreta of ducks, chicks, pigs and cattle are either recycled for use by fish or serve as direct food for fish. Hence, the expenditure towards chemical fertilisers and supplementary feeds for fish culture is not only curtailed to the barest minimum but also there is economy of space. Integration of fish culture and livestock farming is in vogue in many countries and the income realised has been found to be more than that of exclusive fish farming in ponds.

The main potential linkages between livestock and fish production concern use of nutrients, particularly reuse of livestock manures for fish production. The term nutrients mainly refers to elements such as nitrogen (N) and phosphorous (P) which function as fertilizers to stimulate natural food webs rather than conventional livestock nutrition usage such as feed ingredients, although solid slaughterhouse wastes fed to carnivorous fish fall into the latter category.Both production and processing of livestock generate by-products that can be used for aquaculture. Direct use of livestock production wastes is the most widespread and conventionally recognized type of integrated farming. Production wastes include manure, urine and spilled feed; and they may be used as fresh inputs or be processed in some way before use.

Use of wastes in static water fishponds imposes limitations in terms of both species and intensity of culture. Stimulation of natural food webs in the pond by organic wastes can support relatively low densities of herbivorous and omnivorous fish but not a large biomass of carnivorous fish. These biological processes are also temperature dependent. The optimal temperature range is between 25-32°C although waste-fed aquaculture in sub-tropical and temperate zones where temperatures rise seasonally has also been successful. Processing wastes through organisms such as earthworms and insect larvae that feed on them and concentrate nutrients to produce ‘live feeds’ is an alternative approach to raising fish needing high levels of dietary animal protein. Livestock processing can also provide a wide variety of wastes that vary from dilute washing water to high value meat and bloodmeal that can be used as high value fish feeds or feed ingredients. If enough of these types of feeds are available, high density and intensive production of carnivorous fish species can be supported. Aquaculture may also provide inputs and other benefits to livestock production. A variety of aquatic plants e.g. duckweeds and the aquatic fern Azolla have proven potential as livestock feeds; and invertebrates such as snails and crustaceans can be used for poultry feeds.

Based on the type of livestock used for integration there are many combinations in livestock-fish systems. The important ones are discussed below.