Lihou Reef
- ISS004-E-5869
- 12 January 2002
- 03:04 UTC
Lihou Reef (often referred to as Lihou Reef & Cays) is a large, horseshoe-shaped, atoll located in the Coral Sea 575 km southeast from the Queensland city of Cairns — far beyond the boundaries of the Great Barrier Reef. It lies in an isolated and remote oceanic environment at the eastern edge of the Coral Sea Shelf.
Most of the reef system — the largest in the Coral Sea at 2,500 km² — is submerged, although there are 18 small sand cays scattered around its perimeter. The cays — all of which are low and flat — total around 0.91 km² in area and range in size from 0.7 ha to 0.17 km². They are composed mostly of exposed coral sand, rock and coral rubble — five of them are vegetated with grasses and shrubs. The vegetated cays are Turtle Islet, Lorna Cay, and along the southern arm of the reef Georgina Cay, Nellie Cay and Anne Cay. The lagoon itself is roughly 100 km long and 30 km wide, and up to 60 m in depth.
The unvegetated cays on the reef rim include: Juliette Cay, Kathy Cay, Little Margaret Cay, Margaret Cay, Middle Cay, Observatory Cay, Licklick Cay, Betty Cay, Carol Cay, Dianna Cay, Fanny Cay and Helen Cay. Two of the cays of Lihou Reef have scientific installations installed: there is an automatic weather station on Turtle Islet (at the north-western end of the lagoon) and off the eastern tip of the reef a solar-powered navigation beacon has been set up.
Being so remote and away from the the effects of coastal run-off, the waters in and around the reef can be exceptionally clear — with visibility often down to 60 m. With spectacular underwater scenery, fragile sand cays, prolific seabird populations, and Green Turtle nesting sites, Lihou Reef (along with the Herald Cays and Coringa Islets 100 km to the northeast) were designated as strict nature reserves in 1982. The Lihou Reef National Nature Reserve covers 8,440 km².
