Malawi Fisheries Research Institute, PO Box 27, Monkey Bay, Malawi.

Traditional fishing gears and species selectivity in Lake Malawi

A model to describe the relationship between gear selectivity patterns and observed length catch distributions was applied for species caught by the main traditional fishing gears of Lake Malawi. The selectivity function was modelled adequately using either gamma or normal distribution function. Fishing gear selectivity scenarios were investigated in the context of an observed variation in mean lengths of the individual species caught in gill nets, chilimira, beach seines, nkacha and handlines. Dominance of small mean lengths in catches can be used as an indicator of "worse case scenarios" of a fishery. Gear selectivity is shown to have significant impact on the species composition and size distribution, hence this phenomenon is worth considering in assessing the status of the fishery.