A record marine heatwave has caused the worst bleaching event ever for Western Australian coral reefs, affecting even resilient areas.
PERTH: Scientists have confirmed that a marine heatwave off Western Australia’s coast has triggered the worst coral bleaching event on record for the region. The Australian Institute of Marine Science (AIMS) reported that the event was the longest, largest and most intense heatwave ever recorded for the state’s reefs.
Bleaching and coral mortality have been documented across reef systems up to 1,500 kilometres apart. Many sites previously unaffected by bleaching, including the Rowley Shoals, north Kimberley and Ningaloo, were hit hard this year. “There has been little reprieve this time for any of our north-west reefs,” said AIMS senior research scientist James Gilmour.
Preliminary analysis suggests heat stress levels, measured as Degree Heating Weeks (DHW), far exceeded the critical threshold of eight DHWs that often leads to coral death. Early readings show over 15 DHWs across all reefs, with some Pilbara reefs recording up to 30 DHWs — an unprecedented figure.
The findings come as part of a broader concern for Australia’s marine ecosystems. Just last week, AIMS reported that hard coral cover on the Great Barrier Reef had fallen sharply following a record bleaching event in 2024. Scientists warn that sustained high ocean temperatures pose a severe threat to coral recovery across the country.
