Surveys of Octocoral communities, benthic cover and environmental factors on coral reefs of Torres Strait

All surveys were carried out by the principal researcher using Rapid Ecological Assessment. The dataset comprises 33 entries from 7 reef locations.On each reef 1-3 sites were surveyed with up to 5 transects (usually 200-300m long, 1-3m wide for 10-15 minutes) per site at pre-defined depths (1-3m, 3-8m, 8-13m, 13-18m and reef flat).Species recorded: octocorals (soft corals, gorgonians, sea fans, sea whips, sea pens, leather corals, arborescent octocorals, blue coral, stoloniferans), black and wire coral. Note that species are mostly at generic level.Site variables comprise: visibility (a modified Secchi technique - estimating maximum visible distance of a bright object in metres); depth; exposure (very exposed, protected, exposed, moderate); orientation (E, NNE, etc.); formation (Point, Face, Bay/Inlet, Channel); slope angle (assigned to 5° categories); flowspeed (estimated by 5 timings of the traveling speed of suspended particles along a ruler at cm/second); wave exposure (0=sheltered to 4=very exposed); sediment deposit (0=none, 1=thin layer, 2=considerable, 3=thick layer); rubble % cover; sand % cover.Visual estimates of overall abundance (percent cover) were estimated in 2.5% increments from 1-10%, 5% increments from 10-30% and 10% increments over 30%). Categories are: hard corals, soft corals, dead coral, turf algae, coralline algae, macroalgae (conspicuous macroalgae - Halimeda and sargassum - were recorded separately), and total percent cover including sand and silt.Octocoral genera (in some cases species) were given a taxon abundance ranking (0=absent, 1=rare, 2=uncommon, 3=common, 4=abundant, 5=dominant).Zooxanthellate and azooxanthellate richness was calculated based on the numbers of octocoral taxa with (or without) zooxanthellae.Where applicable, samples taken for taxonomic purposes are noted.Site locations: Cumberland Passage, Dungeness, Tuesday Islet No. 4, Thursday, Warrior, Wednesday, Zuna. To survey the cover of the main benthic groups, richness and abundance of octocorals in the reefs of Torres Strait and related spatial and water quality gradients.Because roughly half Octocorals have photosynthetic symbionts they are ideal to assess how biodiversity is related to spatial and environmental factors, and photosynthetic symbionts and energy supply.To examine principal drivers of biodiversity, community composition, and ranges ofcoral reef benthos. Comparable data are held for the Great Barrier Reef, Hong Kong, Palau, Papua New Guinea, and Rowley Shoals (Western Australia).A subset of the data has been provided to the Ocean Biogeographic Information System (OBIS, http://www.iobis.org/OBISWEB/DisplayMetaData.jsp?content=meta/1458.html).