KENYA PROPOSAL

TO ESTABLISH AN AQUACULTURE PROGRAMME IN LAKE VICTORIA TO INCREASE THE FISH AVAILABILITY FOR BOTH OTTERS AND HUMANS

Introduction

Research over the last three years has shown that the diet of otters is an accurate indicator of the state of the aquatic fauna in Lake Victoria and this is therefore a cheap and useful tool for monitoring this ecosystem. 

The effects of the Nile Perch (Lates niloticus) on the cichlid fish fauna of Lake Victoria is well documented, although its impacts on other piscivorous fauna and human fish consumers are less known.  The spotted necked otter (Lutra maculicollis) is a key predator in the inshore and littoral zones, where the communities are dominated bycichlids. 

This zone is also the mainstay of subsistence fishermen, i.e. those who cannot access deep-water fisheries due to their inability to afford fishing boats or larger fishing nets. 

The Problem

Research in Kisumu has found that adult perch and otters compete for the same size-class of fish (8-10 cm) in deeper water.  This has led to increased direct competition between otters and fishermen for fish resources in the inshore and littoral zones.  This competition is revealed in the declining fish catch (Perth:  6.5% per annum, Tilapia:  10% per annum) and rising market price for fish (Perth 55% per annum, Tilapia:  50% per annum) over the last six years.  It is also illustrated by the increase in “net-raiding” by otters and the rising percentage of crab (Potamonautes niloticus) in the otters’ diet.  There are also severe socio-economic and human health impacts, which are still being researched by different groups.

The Solution

Clearly it is necessary for both otters and humans to survive alongside each other and to be able to obtain sufficient fish for their own consumption and to support a sustainable economy.  In order to do this it is proposed to set up a trial programme of aquaculture which is operated by the local community.

This will provide an income for the community, a source of fish for their own consumption and a source of fish for the otters.  It will reduce the competition between otters and humans and can indeed provide extra income to the community through eco-tourism to see the otters and other wildlife.

The community at Kisumu are already quite environmentally aware and there is a group of teachers who run Kisumu Science Teachers Otter Conservation Development Group (KISTOC).

It is proposed to start this programme here and then hopefully other communities on Lake Victoria will also be encouraged to follow their example.

The Method

A 60m gated walkway will be constructed into the marsh, which will lead to a bird/otter viewing hide for tourists.  Four fish culture cages will be built to raise fish for sale, and these will also be used to encourage the otters to visit at particular times and places to allow undisturbed viewing.

The fish reared will be tilapia, which are not carnivorous, but are highly dependent on hippo dung and algae on rocks.  In the cages they will be fed a mixture of cow and chicken manure from the fishermen's homes. There will also be a lot of natural food (insect larvae, algae etc.) drifting through the cages as well, so there will be no little fish to feed the big fish, as in some of the less environmental fish farming industries.