The Great Barrier Reef and Coral Sea

The Coral Sea lies in the southwestern Pacific Ocean, bordered by Australia, Papua New Guinea, the Solomon Islands, Vanuatu, New Caledonia, and the Tasman Sea. The Great Barrier Reef (GBR) constitutes the western margin of the Coral Sea and supports extensive submerged reef systems in mesophotic depths. The majority of research on the GBR has focused on Scleractinian corals, although other taxa (e.g., fishes) are receiving increasing attention. To date, 192 coral species (44% of the GBR total) are recorded from mesophotic depths, most of which occur shallower than 60 m. East of the Australian continental margin, the Queensland Plateau contains many large, oceanic reefs. Due to their isolated location, Australia’s Coral Sea reefs remain poorly studied; however, preliminary investigations have confirmed the presence of mesophotic coral ecosystems, and the clear, oligotrophic waters of the Coral Sea likely support extensive mesophotic reefs. Although mesophotic reefs in the GBR and Coral Sea are among the best-studied globally, most research has focused on only a few sites, and research effort dedicated to mesophotic coral ecosystems remains negligible compared to shallow-water reefs. Despite the lack of ecological data from most mesophotic reef habitats, precautionary management approaches that explicitly considered latitudinal and cross-shelf gradients in the environment resulted in mesophotic reefs being well-represented in no-take areas in the GBR. In contrast, mesophotic reefs in the Coral Sea currently receive little protection.