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Published online by Cambridge University Press: 23 November 2017
The grazing of ducks in carp feeding ponds is a profitable proposition. Ducks droppings are valuable organic manure; 100 kg of duck excreta contains 0.8 kg nitrogen, 1.5 kg phosphorus, and 0.4 kg potassium (Martyshev 1983). Woynarovich (1979) reviewed the practice of growing ducks and fish together. He calculated that one duck produces 6 kg of droppings during a 30-40 d period. At least 500 ducks can be kept on 1 ha of pond for a year, which corresponds to 36000 kgha-1 of duck manure. Also, he estimated that each 100 kg of duck manure, distributed continuously in pond water, might result in an increase of 4 to 6 kg of fish flesh. The aim of this study was to assess the fish production performance between two ponds (with and without duck).