Plastic peril Animals of Galápagos islands living amid mounds of waste

As our fishing boat slows to a halt in a 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 spotted eagle ray glides underneath the vessel.

- Karen McVeigh

The skipper, Don Nelson, steps on to the black volcanic reef, slippery with algae. We follow, past exposed mangrove roots up to higher ground. Pelicans swoop into the trees. This remote archipelago still hosts the unique species, such as giant tortoises and finches, that inspired Charles Darwin's theory of evolution and it is impossible not to be struck by the apparent harmony with which animals coexist with humans here.

But then, a jarring sight: a marine iguana, a species found nowhere else in the world, sits atop a mound of plastic litter-fishing buoys, oil drums, containers, drinks bottles - all pushed on to the reef by high spring tides. The reptile, classed as vulnerable by the International Union for Conservation of Nature (IUCN), is among the species here most at risk from plastic.