Control of Invasive Smallmouth Bass in South African River Systems: Overcoming Practical and Socio-Economic Factors

Monday, August 18, 2014: 5:00 PM
2101 (Centre des congrès de Québec // Québec City Convention Centre)
Darragh J. Woodford , South African Institute for Aquatic Biodiversity (SAIAB), Grahamstown, South Africa
Stuart Barrow , Centre for Invasion Biology, Stellebosch University, Stellenbosch
Karen J. Esler , Centre for Invasion Biology, Stellenbosch University
Brian Finlayson , California Department of Fish and Game (retired)
N. Dean Impson , CapeNature
Olaf L. F. Weyl , South African Institute for Aquatic Biodiversity (SAIAB), Grahamstown, South Africa
North American Smallmouth Bass (Micropterus dolomieu) were imported into South Africa in the early 20th century for sport angling. The species thrived, particularly in the rivers of the Cape Floristic Region (CFR). While the species represents a major threat to the conservation of several endemic CFR fishes, it also supports a thriving recreational sport fishery. These factors make Smallmouth Bass a conflict species where many socio-economic, logistical and legal factors complicate the management of the species. This problem is illustrated using the Clanwilliam Dam reservoir and its tributary, the Rondegat River. Clanwilliam Dam hosts several bass angling tournaments every year, which make a significant contribution to the local economy. The Rondegat River, which flows into the reservoir, contains threatened endemic native fishes, which had been extirpated from the lower reaches by Smallmouth Bass. A decade-long campaign to remove Smallmouth Bass from the Rondegat River using the piscicide rotenone, illustrates the many factors that must be negotiated to successfully manage invasive sport-angling species for conservation. We describe these factors in the context of rapidly evolving invasive species legislation in South Africa, which should improve the control of invasive sport fishes in the coming years.