Water hyacinth on the River mouth to Lake Victoria 2011

Abstract

Aquatic weeds adversely affect water quality, biodiversity, amenity and recreational values of water bodies. Community, social, cultural and economic values derived from such water bodies are therefore impaired. Invasive weeds also have adverse impacts on the structure and functions of wetlands and other riparian ecosystems. Water hyacinth (Eichhornia crassipes (Martius) Solms-Laubach) and other invasive aquatic weeds once established are very difficult to manage and eradication is often impossible. The costs of invasive weeds infestation on the environment, social and economic systems though recognised are difficult to calculate but estimated impacts may be in the range of millions of dollars Lake Victoria the world’s second largest freshwater body was severely infested by water hyacinths, to catastrophic levels in the late 1980’s. The lake’s riparian governments of Kenya, Tanzania and Uganda with support from development partners successfully responded to the menace by applying a variety of water hyacinth control methods such as biological, mechanical and manual/physical removals. Chemical control method remained at only trial level and was never done on large scale. Control of evasive weeds is one of the components of an integrated approach to the management of the LVB