Status and ecosystem interactions of the invasive Louisianan red swamp crayfish Procambarus clarkii in East Africa

There are no indigenous crayfish in continental Africa although there are indigenous crayfish on the island of Madagascar (Hobbs 1988). However, various non-indigenous North American and Australian crayfish have been introduced to continental Africa since the 1970s, notably the Louisianan red swamp crayfish Procambarus clarkii (Girard). This is a relatively large, prolific, aggressive, burrowing crayfish (Hobbs et al. 1989 quoted in Holdich 1999) and it is well documented as an invasive species worldwide (Holdich 1999). Concern about the impact of exotic crayfish on aquatic ecosystems in South Africa (Mikkola 1996) is mirrored for fresh waters in East Africa where P. clarkii has established itself and is spreading (Howard and Matindi 2003).