The best arrangement I have found to stop unwanted use of a pond is to find one or two responsible locals you like and give them permission. Set conditions like how often and "catch and release", then let them know they should "police" the property as if it were their own. They should understand that their priveledges will be revoked if they do not get the trespassing undercontrol or violate any of the conditions you set. This has worked great for me. All those piles of discarded line, six empty beer cans and a syrofoam worm container have disappeared! Also of note, if you have any retriever trainers in your area, they will be happy to provide this service and they don't even want to fish. Just a place to train their labs.
