Globally sharks have been killed for their fins, for their cartilage, for their livers, for their meat. But mostly what has driven some species of sharks to near extinction - including the hammerhead shark - is the new luxury taste for shark fin soup.

I am not in any hurry to grow up.

Throughout all of human history we have consumed the natural world. All creatures do. Birds do. Fish do. Earthworms do. We consume the natural world as a source of our survival. But no creature has ever consumed at the scale that humans have, and now there are seven billion of us. I think the good news is that a large percentage of those seven billion minds can work to make better decisions.

When I write a scientific treatise, I might reach 100 people. When the 'National Geographic' covers a project, it communicates about plants and fish and underwater technology to more than 10 million people.

My parents moved to Florida when I was 12, and my backyard was the Gulf of Mexico.

We want to believe that we can continue doing what we've done for the past thousand years and not worry about the consequences coming back to us.

We have been far too aggressive about extracting ocean wildlife, not appreciating that there are limits and even points of no return.