Australian authorities are sounding the alarm about the health of the Great Barrier Reef's coral.

The government agency in charge of managing the reef has downgraded the long-term outlook for the reef's ecosystem from "poor" in 2014 to "very poor" in 2019.

The report by the Great Barrier Reef Marine Park Authority is the third such snapshot of the reef's health and tracks continuing deterioration since 2009.

Image: Coral reefs can be seen from above on the Great Barrier Reef, located off the coast of Queensland, Australia

This year, it concluded that climate change is still the greatest threat to the reef, a 348,000 square kilometre (134,363 square miles) coral network off the coast of northeast Australia.

The other main threats are associated with coastal development, land-based run-off - where water is contaminated with sediment and pesticides - and direct human use, such as illegal fishing.


The report also noted that there has been habitat loss, degradation and alteration in a number of areas of the reef, affecting populations of some dependent species like reef fish, marine turtles and seabirds.

It said seagrass meadows remained in a poor condition and coral reefs overall have declined to a very poor condition after extensive coral mortality from multiple impacts including back-to-back years of coral bleaching, cyclones and an ongoing crown-of-thorns starfish outbreak.

Image: The reef's outlook was already deemed 'poor' in 2014

"In 2009, the reef was considered to be at a crossroads between a positive, well-managed future and a less certain one," the report said. "In 2014, it was seen as an icon under pressure, with continued efforts needed to address key threats. Since then, the region has further deteriorated and, in 2019, Australia is caring for a changed and less resilient reef."

The Great Barrier Reef Marine Park Authority chief scientist Dr David Wachenfeld said the scientific evidence was clear and everything possible should be done to create recovery windows for the reef.

"Gradual sea temperature increase and extremes, such as marine heat waves, are the most immediate threats to the reef as a whole and pose the highest risk. Global action on climate change is critical," he said.

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Environment minister Sussan Ley said she was not surprised by the downgrade in the reef's condition given the damage done by recent cyclones and latest bleaching events in successive years.

She said her government was "building resilience in this important global reef" and was keeping its Paris commitment to reduce Australia's greenhouse gas emissions.

"I want to make the point that it's the best managed reef in the world," she said.

Image: Illegal fishing.is among threats lowering the reef's outlook

Despite the gloomy prospects, the report also said the reef’s health and condition is variable given its extensive size. It claimed many areas continue to support abundant marine life.

It also pointed out that there are signs of recovery in some species, with humpback whale populations deemed healthy and the southern green turtle population thought to be increasing.

"The window of opportunity to improve the reef’s long-term future is now," the report said. "The reef is core to Australia’s identity and improving its outlook is critical."

A World Heritage-listed natural wonder, the reef contains the world's largest collection of coral reefs, with 400 types of coral, 1,500 species of fish and 4,000 types of mollusc.

According to the World Wide Fund for Nature (WWF), scientists estimate that at current rates of ocean warming and reef decline, most of the world's coral reefs could be lost in the next few decades.