The damned little bast*rds come out of the park that borders my property and they cut, damn and destroy everything in their wake. They nearly flood out the bridge to my house at times. They show up, we go to war, they lose and then return few months later. .22LR to the head is most efficient in ending the war but you have to catch them at dusk or at dawn to even get a shot at them. My late father in law wiped out 26 one year via 1911 and eventually had a construction company owner come in and dynamite their lodge.
Lately they have have stopped showing themselves at dusk and I have the country agriculture agent trapping them. He and the game warden have offered to help the local park set up a control program but the park enviro kooks will have none of it. So they spend their time around the county trapping and killing the overflow from the park of these tooth goomers. California if you do this you are stupid, but then again you have proven time and time again you really are stupid.
I live in Indiana, I have exactly the same issues you do with our lake.