Abstract:

The fisheries resources of Lake Victoria support the livelihoods to the lakeside rural
communities and are vital to the economies of Kenya, Tanzania and Uganda, especially through
fish exports. Management decisions to enable long-term sustainable exploitation of these
fisheries require appropriate knowledge of the fishing effort and catch statistics, as these are
pertinent for evaluating the fish stocks and future prospects of the fishery. Catch assessment
programmes in the Ugandan part of the lake, which should provide this type of information,
collapsed in the late 1980s. This study evaluated the current status of fishing effort and fish
catches and their implications for the management of the fisheries in the Ugandan part of Lake
Victoria. Historical trends in fishing effort and fish catches, total fishing effort in 1990 and
2000, and the current status of fish catch-effort, in the Ugandan part of the lake, were examined.
The findings revealed massive increases in all aspects of fishing effort over the last decade.
Fishing boats approximately doubled, from 8000 to 15 462 boats, and gillnets almost
quadrupled, from 84 977 to 294 529 nets, between 1990 and 2000. Gillnet mesh sizes declined
from mainly 203 and 178 mm to <152 mm, and illegal gillnets <127 mm mesh size increased
from 5 to 18.6%, between 1990 and 2000. Illegal gillnets constituted 53 and 23% of nets in
parachute and paddled Sesse boats (small boats that operate in inshore areas) but only 1.9% in
motorised boats. Other illegal gears, especially beach seines, operated inshore and
indiscriminately catch juvenile fish, also increased considerably. These changes in fishing effort
were coupled with declining catch per unit of effort and are considered indicators of a declining
fishery, suggesting that the current fishing effort is not sustainable. The present exploitation
rates and fishing mortalities of Nile perch (Lates niloticus L.) and Nile tilapia (Oreochromis
niloticus L.) in the Ugandan waters were found to be excessive and require large reductions of
fishing effort to achieve optimum yield. The use of illegal fishing gears and the overall fishing
effort is highest in the eastern zone of the Ugandan waters, and in Kenyan waters at the regional
level. Fishing strategies in the gillnet fishery, the predominant fishery for Nile perch and Nile
tilapia, vary with boat type, suggesting that the regulation of fishing effort should be tailored to
category of boat. Selection characteristics of the main fishing gears/methods in the Nile perch
fishery suggested that fish above the minimum recommended 50 cm TL could be obtained from
catches of drift gillnets with the minimum mesh size at 152 mm. The present long line fishery is
largely non-selective and should be discouraged. Illegal, active fishing with gillnets and cast
nets, which disrupt breeding of tilapiines inshore, prevail in the Nile tilapia fishery, and are
indicative of overexploitation. The present fishing effort for Rastrineobola argentea in Ugandan
waters approximates to the maximum sustainable yield, but is basically restricted inshore, where
the 5-mm mesh size mosquito nets used catch mostly juveniles. Expansion of fishing effort
without endangering sustainability in this fishery would probably be viable with reorientation of
fishing to offshore stocks.
To reduce fishing mortality in the short term, in the Nile perch and Nile tilapia fisheries,
immediate interventions should control the size of fish caught. This should be through
enforcement of existing legislation on fishing gears that target the younger life stages of fish and
regulating the size of Nile perch purchased by fish processing factories. In the long term, the
quantities of fish processed by factories should be regulated by a quota system, consistent with
the fisher}' production potential of the lake. Long lining should be discouraged pending further
scientific investigations of hook selectivity characteristics. The minimum gillnet mesh size limit
should be maintained at 127 mm in paddled boats but raised to 152 mm in motorised boats to
reduce overall pressure on juvenile Nile perch and competition between the large-scale and
small time operators, and promote social objectives of the fishery. Access to the fisheries should
be limited because this is the overriding factor contributing to the present unsustainable status.
Fisheries statistical data collection in Uganda (and Tanzania) should be revived and fisheries
data, collection and reporting systems should be harmonised around the lake. The process of
streamlining institutional mechanisms and legal instruments under which fishing communities
will play important roles in fisheries management (co-management), should be accelerated.
However, for any institutional arrangement to succeed in managing the fisheries of Lake
Victoria, mechanisms for sustainable funding of fisheries activities should be established.