Brian Skerry's Image

It looks like some kind of inflatable pool toy, but what this turtle is munching on is, in fact, a pyrosome: a free-floating colony of hundreds of thousands of tiny tunicates (filter-feeding zooids) wrapped in a gelatinous 'tunic'.

This alone is surprising - leatherbacks tend to dine on jellyfish - but what is more surprising is seeing a leatherback feeding at all. 'Usually, you only see them swimming away,' says Brian. He spotted this individual, nearly two metres long, near the surface in calm water off the island of Pico, in the Azores, Portugal, some distance from where he was snorkelling. As he finned closer, he fully expected the turtle to swim off into the clear blue sea. But it was so engrossed in its meal that he had time to compose a picture. 'The light was tricky,' says Brian. 'I wanted to use ambient light, but because of the position of the sun, it was a delicate dance of slow and gentle movements, trying to position myself to avoid shadows without disturbing the turtle.' Seeing such an elusive creature doing something so rarely witnessed was, he says, 'magical'. Brian continually strives to 'find new ways of creating images and stories that both celebrate the sea and highlight the environmental issues'. He sees this picture as a rare portrait of an incredible survivor - it has a lineage that pre-dates the dinosaurs - now facing a battery of threats, including the warming of the seas as well as fishing, egg-harvesting and coastal development of its nesting areas.