Do literatures searches at a community college or University to see who is studying what. Try to contact these people. Some may ignore you, but writing is a good way to show you are serious. For instance lots of folks want to study behavior but there is very limited funding. While there is not much funding for physiology or parasatoloty there is more, and it is not quite as popular so the chances of getting into the field is a bit better.
Sharks are remarkable at healing after injuries for instance.
Lit search on sharks and those aspects of biology that interest you. Some may ignore you as most researchers work long hours and are busy, but some may answer or at leasst send general lit. If a researcher you really like or admire doesn't write back you might try again if you still like there work, months or years later.