Don,
Your remark about the gators got me to thinking.
I know of a pond "guarded" by a large male black swan. He thinks it is
HIS pond & will charge & flog anyone or anything! You definately don't want to run into him at night!! My brother is Forman at the farm where the swans pond is & he has told some ROFL stories about others encounters with that swan!
I've seen this behavior in white swans also esp. in the spring.
The only problem I can see would be training him to accept those you don't mind fishing. Esp. kids.