Common household condiment could save coral

Australian researchers have discovered an innovative way of stopping the spread of the destructive crown-of-thorns starfish: vinegar. They will now introduce it on the Great Barrier Reef.

Hope is in sight for the beleaguered Great Barrier Reef.

Researchers at James Cook University have shown that vinegar can be used to kill the reef-eating crown-of-thorns starfish without harming other organisms in the sea.

Lisa Boström-Einarsson and her colleagues led a large-scale assessment using vinegar to inject crown-of-thorns starfish at four sites on the Great Barrier Reef over a six-week period. All starfish injected with vinegar died within 48 hours.

The simple and common household chemical has already been proven to be as effective at killing the coral predator as more expensive chemicals. Previous studies also found it to be just as safe in an aquarium setting.

But the recent assessment was the first time researchers had tested vinegar in the open seas and were able to confirm that the weak acetic acid in vinegar is quickly diluted on the reef and poses no threat to other marine organisms.

“We recorded live coral cover, abundance of coral disease, fish abundance and diversity, fish diseases and the abundance of closely related invertebrates before, during and after the six-week study period and found no detrimental effects,” she said.

According to Boström-Einarsson, crown-of-thorns starfish are breeding at epidemic levels and are one of the main reasons for the decline in coral on the Great Barrier Reef along with the mass coral bleaching events of 2016 and 2017.

“There are millions of starfish on the Great Barrier Reef and each female produces around 65 million eggs in a single breeding season. It would take a massive effort to try and cull them all individually, but we know that sustained efforts can save individual reefs.”

Culling crown-of-thorns starfish is critical to protecting coral cover and boosting resilience of the Great Barrier Reef, says Fred Nucifora of the Great Barrier Reef Marine Park Authority. This is all the more urgent in the wake of this year’s coral bleaching.

His agency has now added vinegar to its list of approved control chemicals, allowing operators to apply for permits to start controlling crown-of-thorns starfish using this method. The method will prove especially useful in remote communities and developing countries where access to bile salts – the current substance used to kill the reef-predator – is limited.


Image credit: James Cook University

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