Cage fish farming in the Volta lake and the lower Volta : Practices and potential impacts on water quality

Concerns have been raised about the proliferation of cage fish farming in the Volta lake and the potential water quality impacts. The study was undertaken to determine current cage fish farming practices on the lake, and to assess their impacts on water quality of the lake. Forty cage fish farm operators were interviewed for information on farming practices using structured questionnaires. Water qualities of sites on the lake with, and without cage fish farms were also determined. Results from the survey showed that Oreochomis niloticus , an indigenous species from the Volta lake, was the main species being cultured. Two main feed types were employed by the farmers; 60 per cent being extruded pelletised floating feeds and 40 per cent being non-extruded pelletised feeds. Stocking densities were varied, ranging from less than 50 to over 300 fingerlings m -3 . The water quality results from the study were compared with data collected a decade to three decades ago on the lake to assess changes in water quality. The results did not show marked changes to the water quality of the lake. The study, however, recommends the need for continuous monitoring, and the institution of management strategies for the sector to forestall future eventualities.