Variation of small scale wetland fishery in relation to land use along Mpologoma riverine marsh in Eastern Uganda

Abstract

In densely populated areas such as those in Eastern Uganda where livelihoods demands create immense pressure on environmental resources, small scale wetland fisheries may be disturbed by agriculture practices. The study carried out between 2011 and 2012, investigated the variation of fish catch at the different wetland sites in relation to land use in Mpologoma riverine marsh. Four sites were identified to represent different land uses; intact wetland, minimally disturbed, highly disturbed with small scale farmers and one with a large scale irrigation scheme. Data was collected on water quality, wetland fish species catch and catch per unit effort from the different sites. Conductivity and dissolved oxygen levels significantly differed between sites and explained 72.03% of the variance among sites. Seven fish taxa dominated the wetland fishery. Large sized fish species catch, Clarias gariepinus and Protopterus aethiopicus (range of 0.45 to 38 and 0.25 to 20 kg/day, respectively) was higher at the less disturbed sites than at highly disturbed sites which accounted for over 91.5% of total wetland catch. Tilapia zillii and Oreochomis leucostictus catch were also higher at the less disturbed sites while the small fish species (Haplochomis sp, Clarias liocephalus and C. alluaudi) did not vary with site. Conductivity and dissolved oxygen significantly correlated with the two large fish species' catch but did not correlate with small fish species catch. Agricultural activities in the wetland negatively affected the life history strategies of large fish species, leading to low catch rates at the highly disturbed site. Therefore, there is need to control land use changes to secure high productivity of small scale fisheries in the riverine wetland. Key words: Papyrus wetland, fish, catch, water quality, disturbance.