Method that works best for me is to go get 1 gallon of Dawn dish soap. Go upstream and find where you think their den is and spread the soap in the water all around it and along the dam. Trust me they will get out of there and it doesn’t really hurt the environment. They may come back but you can just do it again. We used track hoes and explosives to no avail. Otherwise use cable snares. This way is just easier and requires less time and effort.
