Title: Assessment of status of the stock and fishery of Nile perch in Lake Victoria -Uganda

Type:
Final project
Year of publication:
2004
Publisher:
UNU-FTP
Place of publication:
Reykjavík
Number of pages:
53
Supervisors: Einar Hjorleifsson

Abstract

Fish stocks in Lake Victoria (East Africa) were boosted in the 1950s with the introduction of four tilapiine species and Nile perch (Lates niloticus) following the collapse of the native fishery due to over-fishing. With annual fisheries production close to 500,000 tons, Lake Victoria remains the most important source of fisheries resources for the three East African countries sharing it (Kenya, Tanzania and Uganda). It took close to 30 years for the introduced species to produce substantial catches reaching a peak in the early 1990s. Current trends indicate that the stocks of the introduced Nile perch are declining. In this study, data collected from trawl surveys between 1997 and 2001, catch assessment surveys (CAS) 2003, and frame survey data (2002), together with published information were used to assess the current status of the stocks and fishery of Nile perch in the Ugandan part of the lake.

This study establishes that of all the factors affecting catch rates from trawl surveys, depth has a profound influence and that variation in years was significant and shows a declining trend. Beach seines harvest a larger amount of juveniles and result in reduced YPR and SSB/R. Revised zoning of the lake based on depth for monitoring purposes is therefore recommended as well as support of methods that will enhance reduction in illegal gears and consequent reduction in harvesting of juveniles. Possible approaches suggested include increased surveillance and co-management.

 

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