From 1987 through 1990 I stocked 180 grass carp in my 6 acre lake. I kept adding them in batches of 30 because over those first 4 years I saw hardly any weed reduction. The lake was about 1/4 covered with pond weeds and algae mats. When the weed reduction started, it really kicked in! Now there's no algae or submerged weeds in the lake.
In summer, the lake tends to become overly green with plankton, somewhat murky, and with patches of floating green slime. We have to treat it with Cutrine Plus a couple of times a summer. My hypothesis is that the planktonic algae is over abundant because there are no weeds with which it has to compete for nutrients. Stocking so many grass carp denuded the lake. My bad! I can still see them lurking in schools beneath the surface. Dozens feed on the grass at the shoreline following a good rain.
Figuring that the grass carp were about a year old when stocked, even the youngest is now 20 years old! This defies almost every estimate I've read concerning their life expectancy (ie. 15-20 years). Can someone tell me how much longer I may have to put up with these behemoths? When will they die? How can I get some of my weeds back?
Thanks!
