Lizard Island

Lizard Island lies about 30km offshore and is a mid-shelf continental island. It is surrounded by extensive fringing reef and has a large, well-developed lagoonal area. The reefs are semi-protected from the prevailing south-east trade winds (March-December, 20-25 knots average) by the ribbon reefs, which lie 20km to the east.

There are no written records of crown-of-thorns starfish outbreaks prior to the 1950s and monitoring of such events prior to the 1980s was quite limited. Three series of outbreaks have been recorded on the GBR and are evident in the photographic sites at Lizard Island. Besides crown-of-thorns starfish, the area has also been affected by bleaching (1982, 2002) and storm surge associated with Tropical Cyclone Ivor (March 1990, which passed 70km north of Lizard Island).

The sites at Lizard Island are located in 5 distinct habitats: fore reef (shallow and deep) and back reef (shallow, intermediate and deep). Site 1 is in 3m of water on a shallow fore-reef. The area is subjected to fairly strong surge and the substrate is mostly a continuous and sediment-free, limestone pavement. Corals from the genus Acropora dominate the site, and although these species are fast-growing they are also highly susceptible to most disturbances. Therefore coral cover fluctuates at the site - plummeting following a disturbance and then climbing fairly quickly several years later. Site 2 lies on the slope below Site 1 in about 12m of water. Loose sediment pours down the slope and through the site and small areas of the reef collapse. Coral cover is low and although there are many small colonies, they have grown very little since the 1980's.

On the back reef, there are 3 sites. Sites 3 lies above site 4 and both have low coral cover. In the past large coral colonies have toppled down the slope and erosion / collapse of the reef is evident. Site 5 is further out on the point and more closely resembles site 1, in that it is dominated by Acroporid species whose cover fluctuates in response to disturbance.

 

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Fore reef

Liz 1 - 3m

Liz 2 - 12m

 

Back reef

Liz 3 - 3m

Liz 4 - 6m

Liz 5 - 2m