The Utilization of agricultural by-products and treated effluent water for aquaculture in developing areas of South Africa

Abstract

The serious shortage of potable water supplies for domestic, agricultural and industrial requirements necessitates an investigation into the optimal utilization of this scarce commodity in South Africa. The multipurpose use of water in agriculture through its effective utilization in integrated aquaculture-agriculture food production systems is one way of optimising the application of such water. In the present series of investigations, agricultural wastes such as chicken, cattle and duck manure were applied as organic nutrient in freshwaterfish ponds with and without supplementary feeds. Fish used in polyculture production for the optimal utilization of the various trophic levels in manured fishpond ecosystems included the European and Chinese carp species and the sharptooth catfish. Supplementary food consisted of 18-45% protein fish pellets. As an alternative to organic manures, treated sewage effluent with fish pellets was used to evaluate its fish-production potential. Fish species used in monoculture and polyculture production included the European common carp and the sharptooth catfish. The role of water temperature on the fish-production potential of these systems was also investigated. The possible value of integrated aquaculture-agriculture systems in protein production in rural community development in South Africa is discussed.