Your pond must be in the People's Republic of Boone County.
I had a similar situation come up with nuisance coons starting around this time last year. An acquaintance of mine caught wind of the fact that I was trapping and eliminating the vermin. He offered to relocate any that I caught. I politely declined and explained that relocation would just make a problem animal a problem for a different human. Dude took offense, called the Conservation department, and ratted me out. That didn't work out the way he was hoping it would. I had previously been in touch with the regional office here in CoMO to make them aware of the situation, and was given their blessing to destroy every one I caught until the problems went away. The agent told him thank you for calling, that they were aware, and please don't call us again to rat on Mr. Augie