The worst coral bleaching in more than 15 years has hit Lizard Island off far north Queensland, scientists say, prompting fears about other northern parts of the Great Barrier Reef.

Lyle Vail, who runs the Lizard Island Research Station north of Cairns, said the majority of the reef flat surrounding the island was showing signs of bleaching.

“We do notice a bit of minor bleaching most summers but this year is exceptional – it’s the worst since 2002 – that year was quite bad,” he said.

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“This year is looking like it could be equally bad or even worse.”

Mr Vail said there was a risk the bleaching would get worse if current weather conditions continued over the next few weeks.

“Unfortunately we’ve got the perfect storm conditions for coral bleaching,” he said.

The flat reef at Lizard Island is more vulnerable to bleaching, researchers say. Photo: Australian Museum

“At the moment we’ve got brilliant clear sunny skies, calm conditions, little tidal movement.

“A lot of that hot water on top of the reef flat is just staying there and cooking the coral.”

Mr Vail said the island’s reef flat was more vulnerable to bleaching, but he had witnessed signs of bleaching in other parts of the reef in the past month too.

“I would anticipate the bleaching even in the northern part of the Barrier Reef is fairly widespread,” he said.

“It can only have gotten worse in those spots since then.

“If these conditions continue there’s no reason why the bleaching won’t pick up in intensity in the more exposed areas – this is extremely worrying.

“These corals that are bleaching have survived two big cyclone impacts in the last couple of years and a crown-of-thorns outbreak.

“You wonder how much more they can take.”

-ABC