Time to have some carp fishing tournaments! That could help a little in thinning your adult sized carp.
If you believe you only have about 20 LMB in the lake, you need to add more top line predators right away! I bet you have more than that though. In that size of a lake, if you only had 20 bass, I highly doubt you would have ever seen one. Carp young of year are excellent forage for predator fish. You should be able to grow out some monster predator fish, though recruitment for your predator fish will be quite low until they start reducing that carp population considerably. Carp really make spawns difficult for other fish.
The way I see it, you could add a massive amount of predators which should help thin your carp to a level that has little negative impact on the lake. Then, your NEW challenge will be trying to establish a strong forage bass, because you'll end up transitioning to a predator heavy lake... which will then need fixing.
12 ac pond in NW Missouri. 28' max depth at full pool. Fish Present: LMB, BG, RES, YP, CC, WB, HSB, WE, BCP, WCP, GSH.
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