Report on the tilapia and other fish and fisheries of Lake Nyasa 1945-1947

Abstract

The 1938-39 Fishery survey found that the Tilapia are the most important commercial fish in Lake Nyasa, and unless the fishery is damaged by over-fishing, they are likely to remain so.They concluded that the existing fisheries were not exhausting the supply of fish and that anincrease in fisheries would be possible without damaging the stock, but stressed that it was vitally important that any enlargement in the fisheries should be carried out under the controlof some officer fully competent to judge the effect of the extension (1942 Report, p. 92). Duringthe war years important changes have taken plenty. The large scale fishing by European andIndian firms in the South-east arm of the lake has developed considerably, and during the pastfew years there has been a widespread shortage of the main inshore-living commercial speciesof Tilapia. During this work it has become clear that the Tilapia form a series of speciesinhabiting inshore to open waters, and it seems that in recent years the balance of the differentspecies has changed, inshore-living species becoming scarce and open water species beingplentiful. This is probably due in part to the high lake level in recent years, but it seemscertain from this study that local overfishing of some of the Tilapia species has occurred in partsof the lake and that serious steps must be taken to help the stocks if the damage is not to proceed.