In the last 5 years or so we have seen a dramatic increase in Grass Carp in the Vaal water system. Further study has revealed some interesting findings. Many Anglers will confirm that we see a increase in Algae and water grass. Now there was never this Problem. What we have noticed is that Fish feed Products being used by anglers is probably the cause for this. Well its actually the preservatives that are used in the feed. What is happening is that preservatives are prohibiting the natural decomposition processes of the feed in the water. Yes fish eat the feed but they do not have stomachs with Acids that break the food down. Instead the fish spend most of its time feeding. Fish are generally the vacuum cleaners of the dams.
Their body absorbs only the nutrients and then passes it out. What is left is still Preserved. The smaller water born insects, blood worms and leaches are supposed to further the breakdown of the feed, yet they are not. They do not go anywhere near feed that has preservatives in it. So this feed swells and becomes sour and the only thing that will attach to it is Algae. Algae will root onto these particles and use it as a floating home. Algae will take its nutrients from the water. In turn we have more Algae in the water and this now forms the perfect foot hold for Water grasses. More water grass means more habitat for Grass Carp.
Now the grass carp are not a Problem just yet. Wait till their numbers explode and then we have a Problem.