Worst Bleaching Event On Record For Western Australian Coral Reefs

Sumaira FH Published August 12, 2025 | 10:15 AM

SYDNEY, (UrduPoint / Pakistan Point News / WAM - 12th Aug, 2025) A marine heatwave off the Western Australian coast was the longest, largest, and most intense on record for the area,
scientists said on Tuesday.

The heatwave resulted in the most widespread coral bleaching event ever recorded for Western Australia, according to the Australian Institute of Marine Science (AIMS).

Experts had reported bleaching and mortality across systems up to 1,500 kilometres apart, AIMS said.

AIMS senior research scientist James Gilmour said reefs that had previously escaped bleaching were hit. "There has been little reprieve this time for any of our north-west reefs. Areas which had given us hope because they'd rarely or not bleached before like the Rowley Shoals, north Kimberley and Ningaloo
have been hit hard this time.

For individual coral reefs, experts were still analysing the Degree Heating Weeks (DHW) - a measure of heat stress on corals. Eight DHWs is the level generally considered severe enough to cause coral mortality, Gilmour said.

Early estimates are over 15 DHWs on all reefs and up to 30 DHWs at some Pilbara reefs, he said, adding that it was a “concerning time” for coral reefs in Australia.

Last week, AIMS reported hard coral cover across the Great Barrier Reef had dropped sharply following a record bleaching event in 2024.