Aventino Kasangaki

Potential Impacts of an Introduced Red Swamp Crayfish on Freshwater Biodiversity of the Rivers Draining the Southern Sector of Bwindi Impenetrable National Park, Uganda

Louisiana Crayfish, the study subject that was introduced into Lake Bunyonyi and has since spread to nearby rivers.

Methods the local people use to capture the crayfish.

The project aims at documenting the current and potential impacts of an introduced Louisiana (red swamp) crayfish Procambarus clarkii on the ecology of the fish fauna in the rivers draining the southern sector of Bwindi Impenetrable National Park, Uganda. A longitudinal survey of fish and crayfish will be done in the southern drainage of Bwindi National park to assess the invasive nature and extent of the crayfish.

In addition, environmental variables will be measured along the longitudinal gradient to determine which variables influence its distribution. The project aims to assess the threats of the crayfish to freshwater biodiversity, a critical step before appropriate strategies can be pursued to address eradication or abatement. The crayfish was introduced into Lake Bunyonyi in the 1970s and has since spread into surrounding streams and rivers with yet to be determined effects on the local freshwater biodiversity and impact on communities´ livelihoods. By studying the extent of spread of the crayfish, we will detect environmental conditions that limit its abundance and dispersal, which inform possible control and management measures.

We will also explore how the crayfish is affecting the fishing activities of the local communities. The relationship between the crayfish and fish species will be explored to document any positive or negative relationships. The local fishermen in the Yamuriro Wetland located outside of Bwindi report fish traps full of crayfish instead of the targeted fish species. This may be affecting the local fishery through reduction of the catch. In Kenya, the Louisiana crayfish has eliminated native plant species in Lake Naivasha and has reduced the abundance of native freshwater crab. There is growing concern that it may severely influence community structure and fish harvested.

The project will clarify the potential threat from invasive species on streams and rivers, habitats that have received far less attention than the larger lakes in the region (e.g., water hyacinth, Nile perch introduction into Lake Victoria). The survey will further document the fish fauna of the southern drainage system of Bwindi National Park with the aim of determining its conservation status.

To read about Aventino's previous project http://www.ruffordsmallgrants.org/rsg/Projects/AventinoKasangaki or for more information contact aventinok@yahoo.com or go to www.itfc.org