Water Hyacinth

Impact of water hyacinth, Eichhornia crassipes (Mart.) Solms-Laubach,

on the fishery of Lake Victoria, Kenya.

M. Njiru, A. N. Othina , and E. Wakwabi

Kenya Marine and Fisheries Research Institute (KMFRI), P O Box 1881 Kisumu kmfkisu@net2000ke.com

M. Njiru P O Box 1881 Kisumu, rmnjiru2002@yahoo.com or kmfkisu@net2000ke.com

Abstract

Due to heavy infestation of water hyacinth in Lake Victoria catches of Clarias gariepinus (Burchell) and

Protopterus aethiopicus (Heckel), which strongly decreased in the 1980s, increased markedly in 1998.

Tilapia catches also recorded an increase following the infestation. Landing areas with sheltered bays,

which harboured more hyacinth mats, had greater catches of C. gariepinus and P. aethiopicus than open

beaches with little hyacinth mats. The increase in C. gariepinus, P. aethiopicus and Tilapia catches is

attributed to increased food availability and breeding areas due to water hyacinth. Reduction of Lates

niloticus (L.) in the lake due to overexploitation could have also reduced predation and competition on

these species leading to their increase

Key words: Lake Victoria, Water hyacinth, Tilapia, Clarias gariepinus, Protopterus aethiopicus

Introduction

Water hyacinth, Eichhornia crassipes (Mart) Solms-Labauch was first reported in the

Ugandan side of Lake Victoria in 1988 (LVEMP 1995; Twongo 1993). Infestation was

suspected to have occurred through Kagera River in Uganda. The rapid expansion of the

weed was reported to show serious economic, social, health and environmental impacts.

Important activities within the fisheries, transport and water quality were affected by

spread of the weed. Large mats of water hyacinth posed major obstruction to transport

and fisheries operations. Delays in delivering fish catches resulted in deterioration of fish

quality and to avoid spoilage operators had to carry ice, which increased operational

costs.

Water hyacinth was reported to impact negatively on the health of...