My personal favorite would be rifle, of light caliber zeroed at about 400yrds. But that takes all your time away from fishing. An easier, cheaper, and less dangerous solution is creative keep out signs.
Maybe something like...
Cotton mouth Sanctuary
Anderson's Alligator farm
Bobcats alive or skinned available here!
Caution! This zone is under quarintene for Rabies out break.
This pond is property of state mental hospital,
sex offenders may be present.
Im sure you get the idea, but the rifle ensures no repeat visitors.... its a toss up.
