I agree george, while its wrong what this guy did, its just a fish, confront him, talk to him about you not agreeing with him following you around. You can take two options here, play small ball and kill him with kindness, tell him where and why the fish are there and how you been catching them, if the guy still has the audacity to come in on you then whip his arse. Or you can belittle him, confront him with the how and why the fish are there and how you are better than him and he couldn't catch them any other way than to follow you around, and he STILL couldn't catch them like you.....Either way...confront him....don't let him pretend its not an issue.