[00:00.511]A single fish can chew its way through a staggering five tonnes of coral a year.
[00:07.357]Smaller parrotfish, colourful cousins of the bumphead,are also at it.
[00:13.597]But they all give a little back
[00:16.351]as the ground-up coral comes out as sand.
[00:21.036]This is island building of a different kind.
[00:24.691]So some of the Pacific's most elegant beaches
[00:27.399]have sprung from a less than stylish birth.
[00:30.338]Above the water, time seems to stand still.
[00:34.200]But the Pacific islands are always changing, if slowly.
[00:39.157]This is Bora Bora,
[00:42.112]a volcano in what could be called "late middle age".
[00:45.885]The sloping flanks have slipped further into the sea,
[00:49.001]pushing the reef away from the shore.
[00:51.962]A lagoon is formed.
[00:54.317]It's a patchwork of coral outcrops and sand.
[00:58.091]Protected from the powerful waves of the surrounding ocean,
[01:02.243]all kinds of animals take refuge in these calm, shallow waters.