Nautilus Wall (Osprey Reef)

Meet the site

Nautilus Wall takes its name from Osprey Reef's population of chambered nautilus (Nautilus pompilius), one of the reef's scientific curiosities. Wikipedia notes that Osprey supports a dwarf population of the species, isolated from others by more than 100 km of deep water. Nautiluses live on the steep outer walls of reefs at depths of roughly 150–700 m, rising toward shallower water at night to feed, which means divers almost never see them in the wild.

That practice involved setting traps on the deep wall overnight, under permit, and releasing the catch at first light in shallow water, where divers can photograph the animals as they pump their way back down.

Without a nautilus, the site is a classic Osprey wall. The face drops into the abyss beneath soft corals, sea fans and whips, with grey reef and whitetip sharks, dogtooth tuna, trevally and schooling anthias. Visibility is usually excellent.

The site suits intermediate divers. Anyone keen on a nautilus encounter should ask the operator before booking, and should follow the guides' instructions closely: the animals are fragile, sensitive to warm surface water and light, and must not be handled or chased.

What you might see

Chambered nautilus (Nautilus pompilius, dwarf Osprey population – encounter by permitted release only), grey reef and whitetip reef sharks, dogtooth tuna, trevally, anthias; soft corals, sea fans, whips

Location

A wall site on Osprey Reef named for the reef's isolated population of chambered nautilus; listed on Mike Ball itineraries and its itinerary map as 'Nautilus'.