how to decde where to contribute to best protect/restore oceans?

As a biologist, conservationist, and avid diver, I'm looking for the best way to make a contribution to ocean conservation. I see postings and advertisements by all sorts of non-profits, and have been investigating a few (starting with Charity Navigator to make sure they are fiscally responsible...) - but there are so many organizations. Small and large. Project AWARE, Blue Ocean Institute, Oceana, Sea Shepherd.

The future of our oceans is at serious risk. Which organizations do you support? Why?