Hogmouth,

Carp are the scourge of the nation. I doubt that there are any public lakes without them. I don't think they are the problem that shad are though, from what I have read before.

Actually they can be fun to catch, and certainly challenge your average bass rig. I used to target them when I was a kid in one of the river flood lakes of the Wabash near Terre Haute.

I doubt that bass anglers introduced them, had to be a live bait angler. Most bass anglers don't use live bait.

I think the shad could never be killed off totally, so keeping them out may be impossible. Keeping them under control might be possible, if additional predators are introduced.

topwater