A field survey was done on the reefs of Torres Strait in February 1995, November 1995 and February 1996. A total of 1,274 sites were sampled with a 20 m by 2 m transect line by divers on the tops of 43 reefs. A total of 374 sites were also sampled by divers along the edges of 41 reefs. At all sites the percentage cover of sand, rubble, live coral and boulders was recorded as were the percentage cover of the dominant and conspicuous sessile flora and faunal megabenthos. Holothurians, giant clams, pearl shells and other large gastropods and conspicuous solitary megafauna were counted and the holothurians were returned to the dinghy and weighed to provide estimates of abundance and biomass.
The habitats on the reefs of Torres Strait were classified by image analysis of Landsat TM satellite data. The habitats were characterised (ground-truthed) in terms of the dominant benthos and labelled based on the data collected during three field surveys.
There were seven main habitat types identified from analysis of the field data and classified satellite imagery: exposed sand; shallow bare sand; mixed sand and hard substrate / coral; shallow rubble and algae / seagrass; medium depth sand and algae; and deep reef edge or lagoon / coral. The field data also indicated that the reefs in Torres Strait were grouped into three main regions: the ribbon reefs along the outside edge of the Great Barrier reef; midshelf reefs up to but excluding the Warrior reef complex; and the reefs on the Oriomo shelf in central Torres Strait including the Warrior reefs, Dungeness reefs and reefs further west along the band of continental islands running north from Cape York to Mabuiag Island mid way across Torres Strait. A series of maps were produced to show the distribution and abundance of reef habitats and the megabenthos sampled on the reefs of Torres Strait. The maps were also stored in digital form in the Torres Strait GIS and are available for further research and monitoring and fisheries management.
Refer to the published reports.
