Sea change Is it time to rewild our oceans and rivers?

Kneeling on the seabed a few metres underwater, I pick up a giant clam and begin cleaning its furrowed, porcelain smile with a toothbrush. It’s a young one and only a handful.

In Fiji, giant clams, or vasua, were so heavily overfished that, by the 1980s, they were thought to be extinct locally. Australian clams were imported to start a captive breeding programme, and subsequent generations of their off spring have been released on coral reefs across Fiji. They’re still vulnerable to fishing but, if carefully guarded, the giant clams do well and have become symbols of healthy coral reefs inside well-managed, marine-protected areas.

A key to their early survival is rearing them in cages to keep them