Features » Understanding the aliens among us

Smallmouth bass Largemouth bass Spotted bass

Illustrations © SAIAB, by Dave Voorvelt, from Paul Skelton 2001. A Guide to the Freshwater Fishes of Southern Africa.

Alien invasive fishes play a major role in southern African aquatic ecosystems.

In this regard SAIAB’s research focuses strongly on the discovery of alien animals and plants, understanding their biology and how they are introduced and spread. A major focus of SAIAB’s approach to researching alien invasive fishes is to develop a better understanding of fishes that are introduced for sport fishing. 

South Africa has a long history of non-native sport fish introductions because few species of native fishes had sport fishing potential. Between 1928 and 1980 introduced fish species fishes established themselves very successfully in most river basins in South Africa.

This resulted in the development of a vibrant sport fishery that, through associated expenditure, contributes significantly to the South African economy. The South African recreational bass fishery is almost identical to that in the United States of America and includes formal ties between the South African Bass Angling Association and the Bass Anglers Sportsman Society in the USA.

Black bass are, however, a major threat to aquatic biodiversity in South African river systems because they prey on and compete with native fishes and invertebrates which has had a negative impact on aquatic community structure and fragments native fish populations. Black bass are therefore specifically listed in the National Environmental Management: Biodiversity Act (10 of 2004): Draft Alien and Invasive Species Lists, 2014 as requiring management. In the long term the goal of such management will be to find a way in which to minimise impacts on biodiversity while maintaining economically important sport fisheries. Read more

Smallmouth bass introduced 1937 Largemouth bass introduced 1928

Spotted bass introduced 1939


Current distributions, introduction date and number of fish introduced into South Africa for smallmouth bass, largemouth bass and spotted bass. (after Picker M, Griffiths C (eds) 2011. Alien & invasive animals: a South African perspective. Struik Nature, Cape Town.)