If the sea is sick, we'll feel it. If it dies, we die. Our future and the state of the oceans are one.

It's taken us a short time to change the nature of nature. In my lifetime, more change than during all preceding human history put together.

I've spent thousands of hours under water. And even in the deepest dive I have ever made, 2.5 miles (about 4 kilometers) down, I saw trash and other tangible evidence of our presence.

The most important part is to take on the challenge of protecting the ocean as if your life depends on it - because it does.

Our job is to keep what is working intact and not destroy what we have got.

I'm not against extracting a modest amount of wildlife out of the ocean for human consumption, but I am really concerned about the large-scale industrial fishing that engages in destructive practices like trawling and longlining.

I'm haunted by the thought of what Ray Anderson calls 'tomorrow's child,' asking why we didn't do something on our watch to save sharks and bluefin tuna and squids and coral reefs and the living ocean while there still was time. Well, now is that time.