The East Auckland current warms the waters around the world-renowned Poor Knights Islands, creating an astonishing environment. Caves and arches hold the only known congregation of stingrays which stack themselves between underwater walls. Demoiselles and Black Angelfish fathers protect their eggs with determination, and must keep a watchful eye on neighbors who will raid their nests in an instant! When disaster strikes and the male Sandagers Wrasse disappear, one of the harem of females undergoes a sex change to pick up the missing male's responsibilities. On land, the Tuatara and Giant Weta fuel an ancient feud, while Gannets rest for their next attack.

• Michael Hurst