As vacationers enjoy the crystal clear water of Bill’s Bay, in the WA resort town of Coral Bay, fish skeletons are strewn among the seaweed.
- WA’s Ningaloo coast has been hit by one of the worst fish kills in over a decade
- About 16,000 dead fish were counted along the coast
- Affected beaches have been cleaned and reopened to the public
It’s a stark reminder of Western Australia’s biggest fish kill event in over a decade and the epic efforts locals made to save the beach before the peak tourist season kicked off.
On March 27, the Department of Primary Industries and Regional Development (DPIRD) launched a fish kill survey after around 16,000 dead fish were counted along the affected beaches of the Ningaloo coast including Turquoise Bay , Bill’s Bay and Yardie Creek.
Bill’s Bay, Coral Bay’s most popular swimming beach, was the hardest hit.
Meanwhile, DPIRD warned people not to enter or fish in the putrid water, which contained high levels of bacteria.
Analysis of water samples from Bill’s Bay indicated that no harmful algae were present, the DPIRD said, but ammonia, nitrates and phosphates were detected, likely the result of decomposition of the spawning corals and fish.
Marion Massam of DPIRD said the department believed the fish kill event was caused by coral spawning.
“Coral spawn itself can use up oxygen in the water and as it breaks down more oxygen is used as part of the breakdown process,” Ms Massam said.
“It reduces the oxygen in the water for the fish. They can end up dying.”
Coral spawning is an annual event, usually occurring after the full moon in March, after the corals are stimulated by seasonally rising water temperatures.
DPIRD said another factor that may have contributed was local sea heat conditions that occurred along the Ningaloo coast in late March.
The department said coral slicks could drift ashore and, when trapped near the coast, could create low oxygen conditions made worse by low tide and swell.
The Ningaloo Coast is no stranger to fish-killing events. Authorities said the last fish kill of this magnitude was 12 years ago.
Beaches reopen to visitors
If you’re traveling to Coral Bay this Easter school vacation, you can thank John Farne for improving the condition of the beaches.
With a few trucks, a bobcat and a loader, John, his friends and the Department of Biodiversity, Conservation and Attractions (DBCA) drove to the beach to clean up the dead fish, which were taken to the dump local.
“It was as bad as it gets and every year the coral spawns and you come out and you say – sniff – ‘Oh, the coral spawns’ and that’s the end. There’s very few of them. But this year has been the exception” he said.
“But as locals we want it to be clean. We can’t do much about the water, but it’s now refreshed. The weather is nice there, so during the Easter school holidays, we’re ready to go.”
On April 8, the DPIRD removed the fish kill alert for Turquoise Bay, Yardie Creek, Point Billie and Jane’s Bay.
Sallyann Gudge of the DBCA said an investigation of the dead fish showed they were all reef-associated species and the ecosystem should recover soon.
“I’m keeping my fingers crossed that all of these things fall into place and fish numbers can come back. A lot of these fish species are recruiting pretty quickly,” Ms Gudge said.
Authorities say they will continue to closely monitor the Ningaloo coast and the fish population.
The DPIRD reminded visitors to exercise caution in the area and not to enter or fish in water that appears smelly and putrid as it may contain high levels of bacteria.
They urge people to report any other fish kills to Fishwatch at fish.wa.gov.au or 1800 815 507.