Fish are usually a major biological component of riverine ecosystems and contribute to biological diversity in a broad sense. The number of fish species present in a river can influence the physical structure and water quality of the aquatic environment and thereby determine conditions for a range of other aquatic and non-aquatic life (Arthington et al 1999).
Despite being the third largest river in Southern Africa the Orange Senqu has relatively low freshwater fish species diversity. Studies have revealed the presence of at least 33 fish species in the Orange-Senqu River. At least fifteen (45%) of the fish species recorded in recent surveys are indigenous to the Basin.
The table below provides a summary of some of the indigenous species found in the basin:
Table: Fish River Species in Orange Senqu River Basin
|
Species
|
Common name
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Indigenous
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Introduced
|
|
Cyprinadae
|
Minnows, yellowfishes, mudfishes
|
|
|
|
Barbus anoplus
|
|
|
|
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Barbus hospes
|
|
|
|
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Barbus pallidus
|
|
|
|
|
Barbus trimaculatus
|
|
|
|
|
Labeobarbus aeneus
|
|
|
|
|
Labeobarbus kimberleyensis
|
|
|
|
|
Labeo capensis
|
|
|
|
|
Labeo umbratus
|
|
|
|
|
Mesobola brevianalis
|
|
|
|
|
Pseudobarbus quathlambae
|
|
|
|
|
Siluriformes
|
Catfishes
|
|
|
|
Austroglanis sclateri
|
|
|
|
|
Clarias gariepinus
|
|
|
|
|
Cichlidae
|
Breams
|
|
|
|
Pseudocrenilabrus philander
|
|
|
|
|
Tilapia sparrmanii
|
|
|
|
|
Anguillidae
|
Eels
|
|
|
|
Anguilla mossambica
|
|
|
|
adapted from Lamberth 2003
In Lesotho fishing does not play a significant role in the economy but is important for subsistence here and there. In Namibia the maritime fishery sector contributes significantly to the GDP. In Botswana's part of the Orange-Senqu River basin fishing is virtually non-existent.The area around the estuary of the Orange-Senqu River contributes significantly to the value of estuarine fisheries in South Africa.
