Sauðárkrókur is about an hour and a half from AEY, weather permitting (and this is a very real factor in the wintertime). It's a decent size town for Iceland, about 2k people, but I'm not sure how much is going on up there outside of tourist season. The school might be able to advise more since I assume you are not the first foreign student in search of part time work.
I don't know about fish farming in that region, but here's a site you can start some hunting on:
as I've said before on this forum though, Iceland runs on personal connections so you'll probably have better luck in person once you arrive.