Extensive culture of fish in ponds

In contrast to intensive culture where the water serves simply to act as a physical support for fish, extensive culture makes use of the natural trophic webs to produce fish which are then eaten by man. Extensive pond culture is particularly developed in China, India and central Europe. The greatest developments are in China where there are more than 0.7 million hectares of ponds and 67% of the world&s;s production of pond fish. Fish are farmed without artificially made diets, but with addition of animal waste products to the pond mainly in Asian countries where supplementary nutrients are costly and/or difficult to obtain. In China and India the ecosystem of ponds is managed highly efficiently for the production of fish. Pond management is also highly developed in the temperate climate of Eastern Europe. This type of aquaculture, where the natural productivity of waters is transformed to products which are consumed by man, is termed extensive aquaculture or sometimes production aquaculture.