Anyone who’s interested in working with bottlenose dolphins, cephalopods and cuttlefish, and seahorses will find marine biology a fascinating field of study. However, I am not really in a position to advise you regarding the best schools to get an education in this field. My school days are long past — I completed my education 35 years ago, so I have been out of the loop for a long while now. I can’t say for sure what the best 21st-century schools might be for studying marine biology.
To the best of my knowledge, all of the schools you are considering have good programs and are well respected. I agree — any of those three schools would be prime locations with a great deal to offer. If I was you, I would try to narrow my choice by finding out more about the staff at these different universities and their areas of expertise. If you can find one of the schools that has resident experts in the areas you are primarily interested in (dolphins, cephalopods, and/or seahorses) or that is conducting field research in related areas, then that may be the best choice.
I will be happy to make some further inquiries for you along those lines, but at the moment, that’s all I can suggest.
Best of luck finding the perfect school for your needs and interests, sir!