As our small fishing boat slows to a halt in a shallow bay south-east of Puerto Ayora, Santa Cruz, in the Galápagos Islands, a green turtle surfaces next to us, followed by a second, then a third a few metres away. A spotted eagle ray glides underneath the vessel.
The skipper, Don Nelson, steps on to the black volcanic reef, slippery with algae. We follow, past exposed mangrove roots and up on to higher ground. Pelicans swooping into the trees and small birds, perching on branches, ignore our approach.
