AUSTRALIA’S ‘OTHER’ REEF

Spectacular but little-known, the Great Southern Reef is a marine treasure that needs protecting says JUSTIN GILLIGAN.

A massive network of reefs lines much of Australia’s southern coastline. It stretches more than 8,000km, from northern New South Wales to the southern tip of Tasmania and all the way to central Western Australia. But whereas the worldfamous Great Barrier Reef is made up of over 2,900 individual coral-dominated reefs, this comparatively little-studied marine feature comprises thousands of cold-water rocky reefs. They range from intertidal rock pools to shallow reefs and deep-water environments dominated by sponge gardens. In some areas, brown seaweeds known as kelp create enchanted undersea forests.

The name Great Southern Reef was coined in a 2016 scientific paper written by a group of prominent marine biologists, who aim to bring this hugely valuable reef network to public attention as a single interconnected system. By giving it a name they hope to raise awareness of the many challenges faced by this fragile ecosystem. Rapid population growth on the adjacent coast is leading to pressure from infrastructure development, pollution and overfishing.

Most destructive of all is the warming climate. Just as warm water causes coral bleaching on the Great Barrier Reef, so too is it having a significant impact on the Great Southern Reef. In fact, Australia’s temperate seas are warming two to four times more rapidly than the global average, largely due to the influence of the East Australian Current off the east coast and the Leeuwin Current off the west coast, both of which transport warm water southwards.

Home to a host of sponges, seaweeds, seahorse-like fish called weedy seadragons, and the giant cuttlefish that wowed viewers of Blue Planet II, the Great Southern Reef is among the most productive marine ecosystems on Earth. Conservationists hope that in future its importance will be acknowledged in the same way as coral reefs. Justin Gilligan was a category winner at the 2017 Wildlife Photographer of the Year