Corals are dying from severe bleaching on parts of the the Great Barrier Reef, with scientists saying they've never felt the water so warm.
Climate change is the biggest threat to the World Heritage-listed ecosystem and every summer experts fear what might unfold.
Recent monitoring around the Keppel Islands off Rockhampton has uncovered the first signs of moderate to severe bleaching this summer, including coral deaths.
The work was done as part of a 25-year program tracking fish and coral changes at 42 reef islands that are a major drawcard for tourists.
Dr Maya Srinivasan, from James Cook University, says water temperatures at the Keppel Islands were well above the summer average, reaching 29C in the water on multiple days of surveys.
"I have been working on these reefs for nearly 20 years and I have never felt the water as warm as this," she says.
"Once we were in the water, we could instantly see parts of the reef that were completely white from severe bleaching. Some corals were already dying."
Bleaching is caused by heat stress. It's not always fatal but corals are likely to die if temperatures remain higher than normal for too long.
Researchers inspected 27 sites at the Keppel Islands. Most showed signs of bleaching and only deeper areas were relatively unscathed.
"Although some corals were already dying, many of the corals could recover if the water cools in the coming weeks," Dr Srinivasan says.
"We did see the temperatures begin to drop towards the end of the trip."
In coming weeks, the team will focus monitoring efforts on the far northern stretch of the reef, as well as Magnetic Island, near Townsville, and the Cumberland Islands, off Mackay.
