Study Site

Rottnest Island (Fig 1, Geographic Datum of Australia 94 Zone 50 South, GDA 94 Z50) is biologically diverse, and includes a wide range of habitats from tropical coral reefs to rocky temperate reefs, seagrass beds and sandy barrens. This diversity reflects the strong influence of the Leeuwin Current, a south-flowing boundary current that brings warm tropical water and species into this otherwise sub-tropical region. As such, the region supports an unusual mix of tropical and temperate fishes [18]. Rottnest Island and its environs are also an important recreational area in close proximity to Western Australia’s state capital, Perth, and as such, marine based tourism and recreational activities including sailing, diving and fishing are highly valued [19]. There is limited commercial fishing in the area and no oil and gas exploration activity. Despite the area’s high conservation and socioeconomic value, there is little information on the distribution of its marine biodiversity, and therefore, the implication of these distributions for management.

Geographic Datum of Australia 94 Zone 50 South (GDA 94 Z50).

Rottnest Island was surveyed in 2007 as part of the Marine Futures Program (www.marinefutures.fnas.uwa.edu.au). Surveys included multibeam mapping, towed video and 349 Baited Remote Underwater Video (BRUV) deployments. From these surveys the species data (fish) and habitat data (three types) used in this study were obtained. These data and the methods used to obtain them are described below.