Rebecca Gredley, Australian Associated Press News.com.au 20 Mar 17;
It will take at least a decade for coral reefs in Western Australia's Kimberley region to recover from recent global bleaching, scientists say.
Inshore Kimberley reefs suffered from bleaching for the first time last year, with local indigenous elders telling The University of Western Australia researchers they had never seen anything like it.
The research team analysed the effects of the 2016 global bleaching, and found that despite coral in the Kimberley being hardier than in other areas, they were not immune to bleaching.
Coral bleaching happens as a stress response, most commonly when coral is exposed to water that is too warm for long enough.
Kimberley reefs experience the world's largest tropical tides, resulting in extreme swings in temperature, which means that about once a month, coral is exposed to air for several hours each day over a few consecutive days, Verena Schoepf told AAP.
"Although this makes Kimberley coral stress-tolerant, it does not make them immune to climate change and extreme heat," Dr Schoepf said.
The team conducted aerial and underwater surveys across the state last year in areas including inshore Kimberley reefs, the Ningaloo Reef, Rottnest Island reefs and reefs along the southern coast.
"Among the reefs surveyed, the Kimberley reefs were most severely affected," Dr Schoepf said.
The research found that more coral died in deeper water than shallow areas, and inshore reefs had about 50 per cent bleaching, whereas 90 per cent of offshore reefs were bleached.
"The mortality is so high that it will take about 10 to 15 years to come back," she said.
"The positive is that the Kimberley is so remote that there are not many other stresses like overfishing."
