Underwater 'Indiana Jones' trying to save the oceans
17 October 2011 Last updated at 00:46 BST
Enric Sala, a Spanish marine biologist, has become the latest National Geographic explorer-in-residence.
Inspired by Jacques Cousteau, Sala has spent much of his life observing and cataloguing the behaviour of the animals under threat in the world's oceans.
Sala says 90 per cent of the world's big fish, such as shark or tuna, have already been lost to over-fishing, and that marine national parks are also being targeted illegally by commercial fishermen.
In this First Person account, at the National Aquarium in Washington DC, Enric Sala tells the BBC why he finds creatures of the deep so inspiring, and how he will use his new title to campaign for policies that help save species from extinction.
For more information: The Ocean - National Geographic