Conserving rare species within Yala swamp, with bias on Lake Kanyaboli

The Yala swamp is Kenya’s largest wetland (17,500ha) located around Siaya/Busia border near Lake Victoria. It harbors 3 satellite lakes; Kanyaboli (10.5 km2), Namboyo (2.0 km2) and Sare (5.0 km2). Lake Kanyaboli is the largest oxbow lake in Kenya and the second largest in Africa. It’s the most economically and ecologically important among these lakes. Recently, a new lake (Lake Bob) was formed below Lake Kanyaboli after one dyke caved in. The lake is a refugium for haplochromines and endemic tilapia Oreochromis esculentus some extinct in Lake Victoria. It’s considered a ‘genetic reservoir’ due to the genetic distinctiveness of its haplochromines. Water quality was measured using standard limnological methods. Fish samples were collected using a fleet of gillnets ranging from 0.5” to 5” stretched mesh size at 0.5” intervals. Monofilaments were used during the day while multi-filaments were used for overnight fishing. Commercial catches were sampled as well. It was observed that stocking of Nile tilapia Oreochromis niloticus has been ongoing since 2001, thereby interfering with the lakes’ ecosystem. It currently dominates by contributing 44.3% of the catch by weight, followed by Clarias gariepinus, at 30.1%, O. esculentus with 14% and Protopterus aethiopicus at 10%. The legal gears for the lakes’ fishery needs to be documented, with the legal size targeting O. niloticus while allowing O. esculentus to escape. Alternatively, the lake should be converted into a community-based national reserve wholly or partially to improve ecosystem health and conserve endemic species with periodic harvesting of Nile tilapia, lung fish (Protopterus aethiopicus), mud fish (Clarias gariepinus) and papyrus (Cyperus papyrus) allowed under supervision. The lakes’ annual fisheries potential is about 3,313.5 metric tonnes. This can be compensated through agro-forestry, beekeeping, conservation agriculture, tourism, carbon credits and hotel industry.