I know certain areas in the Berg river has them for a fact !
I have also seem ones get caught in Sonstraal dam a few years ago , you can't fish there anymore apparently ...
And Behind Willowbridge mall , theres a small channel , theres perch there too , I would assume them that the top part of the channel , which include , Bellwaterpark , Majic forest and the upper Welgedagth pond would have too .
I use to fish these systems often when I was younger .