tein supply for residents is provided by fish, but population growth is rapidly overwhelming the productive potential of the Bangladesh fishery (O' Riordan, 1992). Since the 1960s, per capita availability of fish has dropped from 12 kg to only 7 kg; moreover, among lower income groups per capita consumption is only 4.4 kg. For the poorest of the poor, fish is simply unaffordable (O' Riordan, 1992). Thus, aquaculture plays a more and more important role in meeting the nutritional needs of Bangladesh people.
Bangladesh has a variety of aquaculture and fisheries projects that have been funded by international aid. Many nongovernmental organizations (NGOs) such as PROSHIKA, Bangladesh Rural Advancement Committee (BRAC) and Caritas have been promoting aquaculture development independently through their own extension networks in Bangladesh.
Aquaculture is commonly practiced using polyculture of four to seven species of Indian and Chinese carps in manured and/or fertilized ponds (Wahab et al., 1991). In spite of extensive research conducted on fertilization of polyculture
ponds for carp in many parts of the world, such information in Bangladesh is rather scanty (Haq et al., 1993). Fish production is quite low in Bangladesh, averaging 2,800 kg ha-1 yr-1 (DOF, 1999). In rural aquaculture ponds, fish production is often lower than 1,500 kg ha-1 yr-1. NGOs have been working with farmers to increase fish production; however, different NGOs recommend different fertilization regimes to farmers, and these regimes do not all seem to increase yields. Fertilization regimes should vary with different local conditions such as soil and source water. In some cases the same farmers receive very different recommendations on fertilization regimes from different extension partners. Both over- and under-fertilization may cause adverse effects on fish production, water quality, pond effluents, and economic returns. It is necessary to evaluate fertilization regimes and recommend appropriate fertilization strategies to farmers in order to maximize fish production, maintain good water quality, reduce environmental impact, and maximize economic returns.
The purposes of this study were to evaluate the different fertilization regimes currently used for aquaculture in Bangla
