FASCINATING new research is being done on “the other Mandela” – not our former president, but a major lineage of a small, endangered Eastern Cape fish. The redfin minnow is a wonderful little icon of our province. Although it is small and seldom seen, its existence is key, researcher Bruce Ellender, a Rhodes University icthyology department PhD candidate, explained to me.
In the headwater streams where it lives, it is an integral part of the unique indigenous system of plants and animals that exist there.
This place-specific web of life injects nutrients into the water, it minimises erosion and ensures natural water flow. And this natural flow through the headwater streams is what helps to deliver that precious clean water into the main river systems for us humans, for all our many needs.
Ellender’s study is underway under the auspices of Dr Olaf Weyl of Grahamstown’s South African Institute for Aquatic Biology (Saiab) in Grahamstown. His start point was to try to understand the ecological consequences of alien fish invasion in Eastern Cape streams. But one of the key consequences of this invasion, he has now confirmed, is that it is wiping out the redfin.
Specifically the problem is the North American smallmouth and largemouth bass, two highly aggressive fish which prey on the redfin.
The redfin grows to only about 110mm long and it eats algae and aquatic insects. Besides those distinctive scarlet fins, it is olive brown on top, creamy white underneath and it has a dark band down each
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