Unfortunately, I have to agree with others that a degree is something employers still care about these days (whether or not they should is another matter that is altogether too complicated and likely too controversial answer-wise to get into here), and - as was also pointed out - certain fields are bursting at the seams with qualified (read: certified/degreed) individuals who will almost always be chosen over someone who can’t show those same or greater qualifications.
If college is for sure not something you’re interested in looking into, then you’re pretty well limited to volunteer work or unpaid internships (assuming a more qualified candidate doesn’t beat you out for this), possibly joining on in some kind of aquaculture industry job (I also don’t know anything about how that field operates as far as hiring is concerned), or starting your own business/non-profit to try and help.
Depending on what you’re interested in, opening your own business or trying to join on with another business might not be a bad idea. Aquaculture in particular is a great field for conservation that you could probably get in to, as every fish/coral/whatever sold (either for aquariums or for food) that is captive-bred is one less taken from nature. Similarly, there are various mariculture projects that help by growing out things like sponges for commercial purposes (some people use dried marine sponges for skincare and other things), preventing wild harvesting and frequently helping impoverished communities in the process by providing jobs and external sales to support the local economy. I’m sure there are some other creative ways to help that you might be able to get involved with or to come up with out there, but these are the ones that I’m aware of that actually exist right now.
Anyway, if you’re dead set on avoiding college but trying marine biology anyway, I’d suggest making some phone calls and sending some emails to ask some of the various professional groups out there about what you could do. If conservation through aquaculture is your thing, Rising Tide Conservation, Frank Baensch, and the Horniman Aquarium of the Horniman Museum and Gardens would be great places (or, in Frank’s case, a great person) to reach out to. The Horniman Aquarium in particular is studying captive-breeding of corals - not growing out and fragging, but actual spawning, breeding, and rearing corals - so they’d likely be a great resource to contact about coral reef conservation. If aquaculture is not your thing, but you’re still interested in conservation, you could also reach out to Save the Nautilus or similar groups and ask them for advice. If nothing else, they might be able to point you to someone studying/working with something you’re more interested in that you could talk to.
As a side note, with fish and invert aquaculture, the main issue seems to be cost effectiveness of culturing certain species more than anything at this point, so if you could figure out ways to make the process cheaper, less labor intensive, and/or more effective generally, then that would do a ton of good for the field and for conservation efforts as a whole. Similarly, if you could figure out ways to help corals be more tolerant of heat stress and/or more resistant to pathogenic microorganisms, that would likely do a world of good for the reefs too.
All of that said, if you really want into the field, college would likely be a much easier path to that end for you than most of your other options.
Whatever you decide to do, good luck, and I applaud your desire to help!
