Fish and benthic communities were surveyed on five reefs within the Lihou Reef National Nature Reserve between 15-18 March 2004. The reefs surveyed were Anne Cay, Georgina Cay, Lorna Cay, Middle Cay and Turtle Cay. In choosing survey reefs, consideration was given to the likelihood of the reefs being revisited. For this reason reefs were chosen with sand cays, where previous bird and turtle work had been conducted, and preferably where there was a reasonable anchorage. Also included were reefs visited in 1984 by Ayling and Ayling who conducted the only previously documented survey of Lihou Reef (Ayling AM, Ayling AL (1985) Coral Sea Surveys. Unpublished Report to Australian National Parks and Wildlife Service, Canberra).Restrictions were placed on diving, due to the remote location of the Reserve and surveys were limited to depths of around 9 metres. Weather conditions were not ideal for working on these exposed reefs, with a large swell on most days and winds in excess of 20 knots much of the time. A Cyclone Watch (which formally became Cyclone Grace on 21 March) on the afternoon of 18 March meant that the field trip had to be cut short by several days. Species level data and crude abundance estimates of the benthic communities were obtained using a rapid visual assessment protocol (RAP). Video transect surveys were used to obtain rigorous abundance estimates of biota at a finer taxonomic resolution.Species composition data and crude abundance estimates of the fish communities were obtained using a timed swim, rapid visual census method. Visual census transects provided more rigorous density estimates of a select group of species and a solid baseline for future monitoring surveys.Thirteen species of Holothuria (bêche-de-mer), crown of thorns starfish (COTS) and giant clams (Tridacna gigas and Tridacna derasa) were surveyed along transects, using manta tow, snorkel swims and SCUBA searches.SCUBA searches, along transects, were used to provide information on numbers of COTS in defined size classes, COT scars, Drupella (a coral eating snail) and other sources of coral mortality including coral bleaching and coral disease.Two temperature loggers were also deployed at Turtle Cay, Lihou Reef.
The surveys were undertaken to provide a baseline against which future changes can be assessed and to allow the present 'status' of the reefs in the Reserve to be compared with other reef systems where similar surveys have been conducted.
The Lihou Reef National Nature Reserve (Reserve) is one of two protected areas in the Coral Sea Region. The Reserve is located some 400 kilometres east of Townsville, Queensland. The Reserve was declared on 16 August 1982 and the first plan of management prepared under the National Parks and Wildlife Conservation Act 1975, came into effect in 1989. The Coringa-Herald National Nature Reserve and Lihou Reef National Nature Reserve Management Plan states that the reef system is to be managed as a strict nature reserve - World Conservation Union (IUCN) category Ia. Such reserves are primarily for scientific research to ensure habitats, ecosystems, and native species are preserved in as undisturbed a state as possible. The Reserve also forms part of the National Representative System of Marine Protected Areas (NRSMPA).
