I had the same problem. I took paracord and a large weight and treble hook to make a hand line. Put a piece of chicken on the hook, tied it to my dock, tossed in the water over night. Pulled four 12-15" snappers out of our pond over about 2 weeks. They will continue even after the ducks are grown. The turtle would come up a bite off their feet at night. Not a pretty sight. Haven't had any issues after removing turtles