I was a deckhand two summers ago for the Bristol Bay fishery and it's one of those things that I'm really glad I did, but would never do again. It's an experience of a lifetime and something I will always remember, but man it is definitely no fun while you're there. Some guys love it, but they are all veterans who I'm sure have forgotten what it was like to be a greenhorn. The work is hard, but not terribly grueling...the hardest part is being able to do the work on very little sleep (about 12-20 hours per week). You won't spend hardly any time awake that you are not working. On top of that, you'll need to be focused and learning new things everyday since it'll be your first year. You'd be on a 32 foot boat with only your captain and maybe another deckhand the whole time.
What would really make or break the season is how well you got along with the captain. I HATED mine, which is pretty normal, but miserable. He yelled and screamed at me the WHOLE time, which is also pretty normal. Getting yelled at is tolerable for a while, but 20+ hours per day for 5 weeks straight was a little grinding.
That being said, maybe my experience was soured because I hated the only person I had any contact with for 5 weeks. It's a great opportunity to make some money for a college kid, I was in college when I did it and the money I made lasted me a long time. This really is an excellent and rare chance to do something like this, these positions are actually very sought after and hard to find. Since you are just starting college, it is a great time go up for your first season. If you like it, you'll be able to find work up there the next four summers, and every year you do it gets easier and you make a larger percentage. The catch is (no pun intended) that you aren't guaranteed any money, it isn't that unusual to make less than your plane ticket on a bad year.