It's been ages since I went to Ngor island, and after what turned out to be a hard week's work, I was happy to get back there. The sky was a wonderful kind of patchwork and the light soft; after a week of hard sandy skies, the air felt warm and gentle.

A., a young Senegalese friend, saw me about to swim back across from the island. He asked, with his nervous stutter, if he could come too. He went into a shack on the beach and pulled on a faded pink rash guard, then set off, leading me through the rocks.

A. is a fisherman, and lives in Ngor village, a tightly-packed mound of houses on the edge of the Dakar peninsular. He grew up swimming and fishing with his father and probably never went to school. He can swim the 700 metres across from the island in a matter of minutes, whereas it takes me 20. As I pulled my weary body through the water, A. dove down to the sea bottom to have a look around. Needless to say he doesn't wear goggles.