If I could offer one word of advice....Sunscreen.
I'm with MFJ on this one, Cichlid-Man, sorry, but please, stay stay stay far away from the Marine Biology career path. I was once on it, and unless you graduate from a really good school like Berkley, LIU South Hampton, or U of Florida, there is no future in it. Have you ever watched =JAWS=? Richard Dryfus's scientist character is exactly how post-Marine Biology graduates live, on shoestring budges and out of their suitcases. It is a lot of hard work, blood, sweat, tears, and has absolutely nothing to do with what you think it does. There is nothing glamorous about being a marine biologist (except maybe seasickness and sunburns<G>).
Landing an aquarium job is the most difficult thing in the world to do. I know, I've been graduated four years and still haven't got one. It is the Catch 22. They want someone with 2-3 years experience in an AZA accredited facility, but don't want to hire you so you can get it, no matter how many degrees and SCUBA certs you have. There is such an overflow of Marine Biology graduates on their knees begging for jobs that facilities can have a field day of their picks, and they're looking for PhDs at this point.
So if you want to be a Marine Biologist, you have to start =NOW=. Work in an LFS for whatever they'll pay you so at least you have money. Volunteer at your local zoo/aquarium/nature center/wildlife rehab, what have you, at least 20hrs a week. Even if it has nothing to do with marine animals or fish, most places see that as experience with wildlife and it can only been in your favor. Participate in as many clubs/organizations that have to deal with anything with the waterways of your neighborhood. Get involved with summer camps that cater to marine education, spend a summer at SeaCamp go to SeaCamp.com to see what it is about, I used to work there (on $900 a month, which is not a whole lot of money when you think about it).
Then if you really want to be a marine biologist after all that, you must give yourself over to it, you must be consumed by it, it must become who you are, not just what you do, and it must be your sole driving passion in order to achieve it.
And when the student loans come due after all of that, you'll have wished you were a business major.
Aquaculture is the industry of "growing fish" the same way you grow a crop of corn. There is aquacultures of trout and bass to stock the sport fishing trade. There is an aquaculture for salmon and catfish as food. There is ornamental aquaculture such as for koi and clownfish. There are places that grow seed clams and oysters for shellfishermen, and 95% of all your peals out there come from farm-raised oysters. There are even seaweed farms for sushi wraps and food. Aquaculture is actually a very lurative industry to get into, but you wouldn't necessary study Marine Biology for it. I would take an agricultural route for that, and it is not a glamorous job at all, but it pays well when you can get into it, and some of it is government run on the local level, so the benefits are awesome. But all it boils down to is fish-farming.
Ichthyology is the study of the classification and evolution of fish, and unless you intend to become a lifetime student/PhD college professor, I don't recommend trying to be an Ichthyology career path. It is the same as being a marine biologist, except you concentrate on a single family/species of fish and try to know everything there is possible to know about it so as to be the expert. Some of the research gets downright stupid IMO, such as the rate of neuron fire in the Whatever yacallit species during an ambush hunt. Who really freaking cares except other Ichth geeks, and how does knowing that the neuron fire rate of a hunting Whatever yacallit benefit mankind in anyway other than to enlighten us in the rate of neuron fire in the Whatever yacallit species while hunting? Somehow that information would make me one brain-cell smarter for it, but it would be the first brain cell to die after Friday night happy hour.
~~Colesea