Priorities for research and management on Lake Victoria

Under the worrisomely changing situation in fish species diversity, water environment characteristics, socio-economic dimensions and other ecosystems variables in Lake Victoria, there is an urgent need to put in place effective research and management packages aimed at safe guarding the sustainability of the vast resources of the lake. Priority in have been out-lined to develop strategies which would promote biological productivity and diversity, and socio-economic returns. But given the size of the lake (69,000 km2) and the complexity of dynamic forces which are driving the changes, coordinated approach for research and management among the riparian states and the international scientific community will be required. The task is not only extensive but urgent as well

Major factors to influence the future prospects for fish production and biodiversity in Lake Victoria

Uncontrolled fisheries exploitation, nutrient loading and the proliferation of water hyacinth appear to be the major factors which would strongly influence future prospects for fish production and biodiversity in lake Victoria. There is, thus, justifiable need to tame these factors in order to sustain sound production and biodiversity levels of the lak

Past trends and recent research on the fisheries of Lake Victoria in relation to possible future developments

EAFFRO and UNPP/LVFRP bottom trawl exploratory data have been used to describe the depth distributional pattern. relative abundance and magnitude of the demersai fishes in Lake Victoria. The results have been compared with the commercial catch estimates, and various interpretations of the trends in the annual catches and experimental biomass estimates in relation to possible future developments of the fishery have been suggested. Though it is highly desirable to develop the fishery such as by supplementary trawling, certain social and biological consequences and considerations needs to proceed in graded steps guided by several research disciplines. The past trends of the fisheries of Lake Victoria are briefly considered. Recent exploratory bottom trawl data, by EAFFRO and UNDP/LVFRP, have been used to define demersal fish stocks of Lake Victoria in terms of their magnitude, relative abundance and distribution pattern by depth. Enstence of disparity between the relative abundance of the various species in their commercial catches and in their present biomass estimates is pointed out and the various aspects associated with the necessary modification of the fishing practices are discussed. Further and continuing research of the bio-socio-economic vectors of the fishery will be necessary in order to generate the rationale of an efficient fishing regime for a rational management strategy and realistic utilization of the fishery resource

Past trends, present stocks and possible future state of the fisheries of the Tanzania part of the Lake Victoria

The Tanzania part of Lake Victoria is the most important single fishery resource for the country. Past fishing practice caused disparity between the relative abundance in the catches and in the available stocks by overfishing some species while under-fishing others. Preliminary studies of distribution pattern, biomass estimates, etc, as derived from bollom trawl exploratory data, and the trend of the commercial catch statistics from 1958 to 1970, suggest that many of the commercially preferred species may not have the biotic potential 10 sustain higher yields under present ecological and fishing regimes. Haplochromis and a few other fish might be the only hope. Geographic extension of fishing to deeper waters may not be very promising as species diversificarion and fish density decline with depth. To develop and manage the fisheries, make full use of the resource and ensure economic and biological perpetuation of thc fishery, the appropriate fishing strategy cannot be properly developcd overnight

Batho-spatial distribution pattern and biomass estimate of the major demersal fishes in Lake Victoria

A generalized bottom trawl exploratory survey was carried out on Lake Victoria to: (i) define the distributional pattern and magnitude of the lakewide demersal stocks, (ii) determine the commercial potential of Haplochromis spp. and (iii) evaluate trawling as a commercial fishing technique for Lake Victoria fisheries. Preliminary results suggest that: (i) bottom trawl catches are more representative of the stocks, (ii) species diversification and fish density decrease with increasing mean depth and (iii) at least 80%of the catchable demersal ichthyomass is Haplochromis. Though bottom trawling is a much more efficient fishing technique for the Lake Victoria fisheries, bio-socio-economic consideration impose that mechanization of the fishery should better proceed in graded steps. Besides demographic and nutritional considerations indicate the necessity for rational management and increased direct human utilization of the fishery resource

The role of research in sustainable fishery exploitation, management and development

Fishery resources are very fragile to exploitation if the basic biological intricacies of the available stocks are not taken into account. Research enables the formulation of sound strategies and practices aimed at sustainable fisheries exploitation, management and development. The success of research strategies requires complementary mechanisms to enforce specified measures

Past trends, present stocks and possible future state of the fisheries of the Tanzania part of the lake Victoria

The fisheries resources of mainland Tanzania are comprised of both marine and freshwater sources. The freshwater fisheries, however, are the more important and depend upon Lakes Victoria, Tanganyika, Rukwa, Kitangiri, and other smaller 1akes, rivers, swamps, dams and domestic fishponds. Of these, the Tanzania portion of Lake Victoria, which is about 51% of the whole lake area, is the most important single fishery. Its to

Uganda fish stocks and the necessary measures to obtain accurate information on them

The scope of this paper covers two areas. The first part considers the current stock size of Lakes Victoria and Kyoga, Lake Albert, Lakes George/Edward and the minor Lakes. The second part looks at the necessary measures for obtaining essential information on the fish stocks and the water environment. These measures are aimed at improving the National fish yield while maintaining the water quality for the different user interest

The fishery of Lake Victoria, Uganda

The only comprehensive assessment of fish stocks in Lake Victoria was undertaken during the period 1968/71 by the UNDP/FAO/EAFFRO. This work established for the first time an order of magnitude for the standing stocks of fish at 248,029 metric tons, in the Uganda portion of the lake, of which 205,592 tons (83%) comprised Haplochromis (NKEJJE). The other dominant species (in order of dominance) included the tilapiines (NGEGE), Baqrus docmac (SEMUTUNDU), Ciarias mossambicus (MUDFISH), Synodontis victoriae (NKOLONGO) and Protopterus aethiopicus (MAMBA), Lates niloticus (NILE PERCH) then comprised less than 0.1% of the standing stock (Kudhongania and Cordone, 1974). Rastrineobola argentea (MUKENE), a pelagic shoaling species, was also rare. About 80% of this standing stock was concentrated in shoreline waters of 0-49 metres deep, mostly within the artisanal fishery zone. The vast open and deeper waters had only about 20% of the standing stock

Water quality management needs in Uganda

About 17% of the surface of Uganda is covered by water. Some of the water systems (Lakes Victoria, Edward, Mobutu and river Nile) are shared with countries (Kenya, Tanzania, Zaire, Sudan etc.)