SYDNEY, July 11 (Xinhua) -- An annual "check-up" of Australia's Great Barrier Reef has shown a mixed year for the world's largest coral reef system, with the Australian Institute for Marine Science (AIMS) releasing their findings on Thursday.

AIMS' annual Great Barrier Reef Condition Report, which has been running for over 30 years, provides a vital continuous record of change in the reef which occupies much of Australia's tropical northeast coastline.

This year it showed that while the southern and central sections of the 2,300-km-long system are reducing in size, the northern region has partially stabilized.

Average coral cover in the northern region increased from 11 percent in 2017 to 14 percent in 2019, although is still lower than 30 percent in 1988 when the study began.

The central region's highest recorded average coral cover was 22 percent in 2016 and reduced to 12 percent this year, while the southern region had 43 percent in 1988, compared with 24 percent this year.

"Our long-term monitoring has shown that 10 years after Tropical Cyclone Hamish caused widespread damage in the southern region, particularly in the Capricorn-Bunkers in 2009, these reefs are still recovering," monitoring program leader and ecologist Dr. Mike Emslie said.

Emslie said that major disturbances such as crown-of-thorns starfish outbreaks, further cyclones, and coral bleaching events have hampered the reef's efforts to reestablish coral growth.

"We know reefs can recover given time and the right conditions, but there has been little relief from disturbances in recent years to allow significant recovery to occur," he said.

The Great Barrier Reef is an important national icon for Australians, as well as providing billions of dollars each year to the economy through visitors coming to experience its unique natural beauty.