To add, I have gotten complaints of how if I am grouped with another person, my level affects their experience gain, not allowing them to get any experience at all even from the docks. In my opinion being grouped for fishing shouldn't affect experience gain at all. I don't like fishing alone.
I remember from beta that if you were in a group at all, you wouldn't get any xp, regardless of where the group member(s) are. I think it was a bug, and supposed to be fixed. Did you make a post in the bug reports or PM an Admin?