If you've visited Coral Bay in recent years, you might have been surprised by the apparent decline in coral health in the main snorkeling areas. Many tourists mistakenly attribute this to climate change, a global issue affecting coral reefs worldwide. While climate change is undoubtedly a significant threat, there's a more specific reason for the changes at Bill's Bay in Ningaloo Reef.
In March 2022, Coral Bay experienced a massive coral spawning event. While coral spawning is a natural phenomenon that occurs annually in the autumn, this particular event was unlike others. An offshore tropical cyclone disrupted the usual dispersal of coral spawn, trapping it near the beach. This spawn eventually washed on shore and began to decompose. The decomposing coral spawn depleted the water's oxygen levels, leading to the suffocation of marine life in the bay.
The coral in the bay was stressed by the low oxygen levels and rising water temperature and began to bleach. For about two weeks, the beach between Point Maud and the Boat Ramp was a tragic scene. Fish, eels, rays, clams, and other creatures washed up on the shore, unable to breathe in the oxygen-deprived water. The nutrient levels this created led to an algal bloom which in its weakened state the coral could not defend itself against. The vast majority of coral species, such as branching, and plate corals succumbed to the algae.
While it's heartbreaking to see, this event is a natural part of Coral Bay's cycle. Historical data has shown smaller events over time with catastrophic events occurring on cycles closer to 20 years.
Is any coral alive in Coral Bay?
Whilst at there was concern the entire bay had been affected. Investigations once the water was safe to swim showed that the extent of the coral death was roughly from the boat ramp to Point Maud. Within this area most of the branching, and fast-growing corals died off. However certain species proved to be more resilient. These are known as massive corals such as porites and favia.
One iconic survivor, which caused concern as it was completely bleached at the time, was 'Ayer's Rock', a roughly one-thousand-year-old porite. This incredibly resilient coral always has been and continues to be a vibrant fish cleaning station today.
Recovery of the bay has occurred previously and will occur again due to the surrounding eco system being incredibly healthy, herbivorous fish have migrated in and doing the jobs that are needed to be done preparing the old coral structures for settlement of new corals in subsequent reproductive events.
The outer reef was unaffected quintessential spots like 'The Maze', 'The Aquarium' and 'Asho's Gap' continue to thrive.
How long will it take to recover?
The process of recovery is well underway with the constant removal of algae and recent spawning events. Like any eco-system the fast-growing colonizers will be the first to appear. Within five years you'll be able to see the new coral growth, within ten it will be looking significantly healthier and within twenty hopefully it will have recovered to the state it was in prior to this event.
What can you do while visiting to ensure the best recovery?
While the recovery process may take time, there are steps we can all take to support Coral Bay's marine ecosystem. By choosing reef-safe sunscreen, avoiding touching coral, fish in fishing zones only and leaving no trace, we can help to protect this fragile environment.
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