Sharptooth catfish have invaded most of the big dams in the Western Cape by now. In many of these dams, including Theewaterskloof, Brandvlei/Quaggaskloof, Misverstand, and Clanwilliam and Bulshoek Dams, their populations boomed, and they’ve become very abundant (and basically a nuisance to many anglers) across these waterways, to the extent that they’ve also migrated kilometers upstream and downstream from these dams and right up into the catchment areas and down into the estuaries of the mainstream rivers.
Scientists are monitoring this catfish invasion, but the future impact of these large predators on other fishes is unclear at this stage. Now one would think that other fish species potentially at risk – falling prey to the wide gapes of adult catfish – would be indigenous fishes like witvis (in Brandvlei/Quaggaskloof) and Clanwilliam yellowfish (in Bulshoek and Clanwilliam), and other popular sport fishes like largemouth, smallmouth and spotted bass (basically everywhere), but did rainbow trout cross anyone’s mind? It certainly didn’t pop up in my head, that adult sharptooth catfish could pose a threat to trout in our fabled Cape Streams…
Chunky smallmouth bass in our Cape Streams could become scarce due to the on-going (and escalating) sharptooth catfish invasion…
A lekker rainbow trout caught in a classic whisky-coloured Cape Stream.
That was until I recently went to look for some river rainbows on a dry-dropper rig and while the trout were there, as expected, I experienced a full-on catfish run in a Cape Stream. So instead of presenting flies to trout while wading upriver, I got to sight-fish large, dark, slimy cats slithering through shallow runs and holding in tailouts during what looked like a mass catfish spawning event!? There is clearly a new top predator in our headwaters and soon Cape Piscatorial Society members may be presenting nymphs at large catfish, instead of hunting trout in our freestone rivers…
A nice rainbow that was sitting in the tailout of a pool, holding right next to a sharptooth catfish…
