Local marine biologists say the annual event, off the coast of Queensland in northeastern Australia, could be among the biggest in recent years.
Conservationists say a new funding to restore and protect the Great Barrier Reef is "an important step" while the biggest threat to the reef is global warming.
A study conducted by Deloitte Access Economics found that the Great Barrier Reef is worth $42 billion and underpins 64,000 jobs.
Seven percent of Australia's Great Barrier Reef untouched by mass bleaching
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