Are fisheries management, measures in Lake Victoria successful? The case of Nile perch and Nile tilapia fishery

Abstract

Population characteristics from samples collected during bottom trawl surveys of 1998-2000 and 2004-2005 were compared to evaluate the success of the management strategies put in place for Nile perch, Lates niloticus and Nile tilapia, Oreochromis niloticus fisheries in Lake Victoria. Data were analysed using FAO-ICLARM stock assessment tool. Length at 50% maturity (Lm 50 ), asymptotic length (L ¥ ) and maximum age (t max ) attained have decreased whereas fishing mortality (F) and growth curvature (K) have increased between the two sampled period. Over 98% of L. niloticus and 60% of O. niloticus caught were immature and the commercial landings indicated a general decline especially in L. niloticus catches in the past few years.The observed changes in population characteristics and decline in catches can be attributed to failure in controlling increasing exploitation in the lake. The number of fishers, boats and gears are on the upward trend. Ban fishing gears like beach seines and small mesh sized gillnets are still prevalent in the lake. Active gillnetting and use of nets that fish the entire water column are increasing in the lake. To sustain the fishery of Lake Victoria, the current situation requires immediate action to be taken. There is a need to re-evaluate the effectiveness of the current management measures with the possibility of adopting new ones that can save the declining fishery. Enactment of new fishery policies should provide for and strengthen the current regulations and their enforcement structures especially in embracing principles of co-management to enhance the whole management process.

Microcystin concentrations in Nile tilapia (Oreochromis niloticus) caught from Murchison Bay, Lake Victoria and Lake Mburo: Uganda

“…The generalist filter feeding Nile tilapia is a very important economic fish in Lake Victoria (OgutuOhwayo, 1990;Njiru et al, 2007) and Lake Mburo (Bwanika et al, 2004;Nagayi-Yawe et al, 2006). Nile tilapia, consumes large amounts of the cyanobacteria Microcystis and Anabaena in its diet (Balirwa, 1992).…”

Are fisheries management, measures in Lake Victoria successful? The case of Nile perch and Nile tilapia fishery

“…However, even with this decline in catches, Lake Victoria still supports a valuable fishery (Abila, 2000;Yongo, Keizire & Mbilinyi, 2005). Currently L. niloticus, R. argentea and O. niloticus constitute the most important commercial fishery in Lake Victoria with a total annual catch estimated at 500,000 t with an export valued at US$250 million (Yongo et al, 2005).…”

Artisanal Fishery of the Exploited Population of Macrobrachium vollenhovenii Herklot 1857 (Crustacea; Palaemonidae) in the Asu River, Southeast Nigeria

“…Experience of other geographical regions has shown that because of stock depletion, fishers have to put in greater efforts, including the use of smaller mesh sized nets/baskets and increase in fishing hours, to meet the demand. Such increased efforts will lead to larger cropping of juvenile prawn and will inadvertently accelerate stock depletion and impair recruitment (Njiru et al 2006). The likelihood that the number of fishers and fishing hours will increase tremendously in the foreseeable future is eminent and should be prevented.…”