The intriguing dynamics of Rastrineobola argentea fishery in the Kenyan waters of Lake Victoria

Abstract

The Lake Victoria ecosystem once hosted a diverse fish community dominated by a large species flock of haplochromine cichlids. Today this fish assemblage is highly altered by anthropogenic activities, with at least half of the indigenous species either extinct or very rare. The fishery has been reduced to three fishes of economic importance: introduced Nile Perch (Lates niloticus) and Nile Tilapia (Oreochromis niloticus), and Indigenous Minnow, Rastrineobola argentea, locally known as Omena. Decline in fish stocks in the lake is still continuing; however, in order to rejuvenate stocks therein, a fishing ban (closed season) was imposed in November, 2001 between 1 April and 31 July of each year through a Kenyan government gazette and legal notice (L.N.214/2003). The ban was not only intended to protect the Omena fishery but was also used to anchor efforts towards protecting and rejuvenating dwindling stocks in the lake. However, whether the Kenyan approach has made any gains for the region is still equivocal. It is on this basis that we reviewed existing information on both historical and current stock levels of R. argentea, and the closed fishery implication on the livelihoods of the riparian communities. Our review results indicate that Omena biomass in Lake Victoria has increased considerably from approximately 500,000 MT in 2001 to 911,328 MT in 2011. Rastrineobola argentea is now the most important fish stock by mass in Kenyan waters contributing almost 61.5% of the total fish landings (10,339.0 MT), with ex-vessel value of total fishers’ earnings of about Kshs. 207 million (approx. USD 2.5 million). In response to the emerging uncertainties regarding the closed season or ban, we recommend and advise for a balanced, win-win approach balancing the biological cycle of stocks against the socio-political and economic issues, in order to sustain the stocks and enable the fisher folks to eke their daily food and earnings.

Keywords:

• sustainable exploitation
• fishing ban

Acknowledgements

We thank the entire Board of Management of the Kenya Marine and Fisheries Research Institute (KMFRI) for their support and allowing us to use institution facilities during our research. The authors are grateful to the Lake Victoria Fisheries Organization (LVFO) who readily provided data acquired during regional acoustics, catch assessment and frame surveys for our review. We are also thankful to Professors Sarah Glaser and Cullen Hendrix for their invaluable reviews and comments on the manuscript.