03/28/2011 at 01:00 AM EDT
Cofounder of the conservation organization Oceana, the actor has written a book about how we can save our seas.
THE BIGGEST PROBLEMS?
Overfishing: 30 percent of the world's fisheries have collapsed, and 90 percent of the big fish that existed in the '50s are gone. Acidification, which is destroying our reefs ...
WHAT CAN BE DONE?
We need to create no-take zones so the fish rebound. Attack the problem country by country.
WHAT CAN INDIVIDUALS DO?
Eat wild instead of farmed fish, for one thing. Fish farming results in overfishing as forage fish are used to feed the farmed fish.
Go to the beach, look at the sunset, and remember how much you love the ocean. You have to tackle these problems with a light heart.