A Study of a Small Basket-Trap River Fishery In Kenya

Abstract

An analysis is given of seven months' operation in 1957 of a small basket-trap fishery in the Ragati-Sagana river junction area, at an altitude of 3,940 feet in Kenya. The hydrological regime of the two rivers during this period is described, both rivers showing the twice yearly flood periods typical of most eastward flowing rivers in Kenya, with which are associated changes in conductivity and turbidity only three genera of fish enter such a fishery, two species of Anguilla, and one each of Barbus and Labeo. Though total catch showed a diminution in this period in spite of increased effort, this does not necessarily indicate a diminution of total stock available, since all these fish are migratory. Although the effect of fishing on total fish stocks is thus not clear over such a short period, the fishery appeared to alter the composition of the local fish stocks, Labeo dominance in early catches being replaced later by a Barbus dominance. It is suggested that this change may be due todifferences in the biology of the two genera, and data available from the trap catches concerning migration, food, sex ratio, maturity state and length /weight relationship are discussed. Studies on age and growth of these fish are not yet complete. The results have shown that such a small basket-trap fishery is relatively inefficient from a cash profit aspect, but it can nevertheless contribute materially on an individual subsistence basis to alleviating protein malnutrition, since the supply, though small, is fairly regularly obtainable at negligible cost in such rivers.