The Most Biodiverse Dive Sites in Northern Territory

The ranking counts the species and groups recorded in each site's marine-life entry, which favours sites that have been surveyed and written about carefully. That is a reasonable proxy for biodiversity, and it produces a list that experienced divers will recognise: the great macro piers of Victoria and South Australia, the subtropical convergence sites of southern Queensland where tropical and temperate species overlap, and the pinnacles of the Ribbon Reefs.

It undercounts the Great Barrier Reef, where every outer-reef site has hundreds of species and the site records simply say 'reef fish, corals'. It also reflects the temperate south's real strength: southern Australia has the highest proportion of endemic marine species of any temperate coast on earth, and the sponge gardens of Port Phillip and the gulfs are where they live.

The subtropical coast from the Gold Coast to the Sunshine Coast and around to Bundaberg is the biodiversity sweet spot for a visiting diver. The East Australian Current brings tropical species south; the temperate species reach north; and structures like the Brisbane, the Seaway walls and Wonder Reef give them all somewhere to live. Winter brings grey nurse sharks and clear water, summer brings mantas and leopard sharks, and the macro life is there all year.