For divers exploring Western Australia’s reefs, the underwater world has changed dramatically. A record-breaking marine heatwave—the “longest, largest and most intense” ever documented in the region—has left vast stretches of coral bleached or dead, from the World Heritage-listed Ningaloo Coast all the way to the remote Ashmore Reef.
Bleached staghorn coral (Matt Kieffer, CC BY-SA 2.0)
Scientists say some sites have lost more than 90 percent of their living coral, with the Rowley Shoals—once a dream destination for pristine reef dives—among the hardest hit.
“When you have more than about 75% of corals that have bleached or died, it can be very hard to find any healthy corals.”
— Dr James Gilmour, senior researcher, Australian Institute of Marine Science
What divers will see
Divers visiting WA reefs in the coming months may notice large patches of ghostly white coral, a clear sign of bleaching. In the worst-hit areas, divers are likely to see skeletons of once-vibrant colonies now overgrown with algae. Schools of reef fish are still present, but their habitats have been severely altered, and the overall sense of colour and life is diminished.
On reefs that experienced medium-level bleaching (11–30 percent), divers may still encounter surviving corals alongside stressed ones—giving a glimpse of resilience and the hope of recovery, if conditions improve.
The bigger picture: Tourism and reefs
The news is difficult not only for marine scientists but also for dive operators and tourism communities that rely on healthy reefs. Locations like Ningaloo and Rowley Shoals are world-renowned dive sites, drawing visitors for their corals, whale sharks, and rich marine life. Prolonged reef damage will make these ecosystems less attractive and much harder to sustain.
Still, dive tourism can play a role in the solution. Many operators are joining awareness campaigns and encouraging visitors to experience the reefs responsibly—supporting local conservation and reminding people what is at stake. However, the big problem is global warming.
A global crisis underwater
This WA bleaching is part of the largest global coral bleaching event ever recorded, which began in January 2023 and is still unfolding. Over 80 percent of reefs worldwide have faced heat stress severe enough to trigger bleaching, including Australia’s Great Barrier Reef, which has just seen one of its steepest annual coral declines.
“Climate change is driving these events, which are becoming more frequent, more intense and more widespread, giving our amazing, valuable coral reefs little time to recover. And they need 10 to 15 years to recover fully."
— Dr James Gilmour, senior researcher, Australian Institute of Marine Science
What divers can do
- Dive responsibly: Avoid touching coral or stirring up sediment. Even stressed corals can recover if left undisturbed.
- Support reef-friendly operators: Choose dive centres involved in monitoring, conservation, and education.
- Raise awareness: Share your reef experiences to highlight what’s happening beneath the surface.
- Push for climate action: As scientists stress, cutting greenhouse gas emissions is key to giving reefs a fighting chance.
A message of urgency
For now, divers may find both heartbreak and beauty beneath WA’s waves: hauntingly pale reefs, but also the resilience of marine life that persists despite the odds. But scientists warn that without rapid climate action, the “rainforests of the sea” will become rare in our lifetimes.
