They are especially vulnerable because they swim slowly and close to the surface.

BBC: Tagging whale sharks in the Maldives

He said they could not swim on their backs because their disability prevented their backs from making the arch needed to swim.

BBC: NEWS | Health | A bike for the paralysed

The family of a man swept into the sea in Blackpool during gale-force winds say they "fear the worst" because he cannot swim.

BBC: Paul Morris

She talks to Olympians and to open-water champions like Lynne Cox to find out why they live to swim, why swimming is man's most sensuous sport (because skin is his largest sensory organ) and why it keeps your arteries elastic, your joints supple, is good for your heart as well as your brain, and offers more than a cursory help in the fight against ageing.

ECONOMIST: Lynn Sherr��s new book offers all the skinny on dipping