I read that you’ve spent 7,000 hours underwater. True?
That’s not counting the shower.
Just actual scuba diving. It’s almost one year of your life. So when you go down now, what excites you?
You never know what you’re going to find, but you know it’s going to be good. We’ve only seen about 5% of the ocean as a whole. We’re just getting started as far as ocean exploration is concerned. It’s our life-support system, and we’re just beginning to understand how it functions and really why it matters to everyone everywhere.
How did a girl from New Jersey get into the ocean?
I suppose on the beach. When I was 3 years old, I got knocked over by a wave and the ocean got my attention, and it’s held my attention ever since. Life is in the ocean. The history of life is there.
Your work started during the 1960s. Was that the golden age of ocean exploration?
It’s still happening. It’s now the platinum age.
When did you switch your focus from exploration to conservation?
It seemed to me, even as a kid, that we can’t put things back together again. We’re destroying the ancient systems in the ocean as if they will constantly renew, and now we know they don’t. I could see that for myself. The transition has been gradual and become more intense because our destruction has become more widespread and obvious.
And how will Mission Blue–the foundation you created and the subject of a Netflix documentary–change that?
Mission Blue began when I won the TED Prize in 2009 and was granted a wish. I said that I wished for public support, help to ignite support for exploration, for new submarines, to get people behind the concept of Hope Spots–protected areas in the ocean large enough to restore and maintain the integrity of the blue heart of the planet, the ocean. Not just because it’s beautiful, not just because I’m a whale hugger or a fish hugger–I am, but that’s really not the point. I’m mostly a people hugger. I know that the ocean keeps us alive.
There are national parks, but is there anywhere near that kind of protection when it comes to marine parks?
It’s just beginning to catch on. About 14% of the land globally has some form of protection as a park reserve or wildlife area. But a fraction of 1% of the ocean is fully protected, where the fish in the sea have some safe havens.
When you go to the Tokyo fish market, what do you see?
It’s like a slaughterhouse. Slaughter in the ocean. Just taking wildlife on a scale that is unprecedented in the history of the world.
How do you stay hopeful that we’ll be able to fix problems that seem so insoluble?
The biggest reason for hope is knowing, because when people know, they might care. Ocean acidification, climate change, whatever it is–the world that I knew as a child doesn’t exist anymore. I tell people I come from a different planet, because I do. The planet I knew is gone. And now we live on a different one that has all these other issues. But protecting and holding steady the places that are still in pretty good shape, that still are resilient–it’s one of the best recipes for giving us some shield against the warming.
It makes me feel kind of depressed to hear about all this going on. How do you deal with it?
We’re the luckiest people ever, if you think about it. The bad news is there, but the good news is we’ve got the knowledge, we can see what the future will be if we keep doing these stupid things. And I’m an optimist, because I think it’s happening. There’s time to do something about it before it’s too late to make smart decisions.
This appears in the October 06, 2014 issue of TIME.