Vinegar may help protect Great Barrier Reef

Melbourne

Common household vinegar may help protect Australia's iconic Great Barrier Reef by effectively and quickly killing the coral-munching crown-of-thorns starfish, scientists said on Thursday.

The innovative method of killing crown-of-thorns starfish (CoTS) is safe to other marine life and will now be introduced on the reef.

The Great Barrier Reef has been exposed to multiple disturbance events in recent years, including the 2016 and 2017 mass coral bleaching, three severe tropical cyclones in the past three years, and the ongoing CoTS outbreak.

CoTS are breeding at epidemic levels and are one of the primary reasons for the decline in live coral.

Researchers at James Cook University in Australia led a large-scale assessment using vinegar to inject CoTS at four sites on the reef over six weeks.

They had previously shown that the simple household chemical was just as effective at killing the reef-eating starfish as much more expensive chemicals with complicated processes.

The latest tests show vinegar has no ill effect on other organisms in the sea.

"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,” said Lisa Bostrom-Einarsson from James Cook University.

"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," Bostrom-Einarsson said.

"Given the diverse range of disturbances that are currently affecting the reef, we need to give it the best possible chance to recover," she said.

The safety of vinegar had previously been assessed in an aquarium setting where species known to feed on or associate with CoTS were placed in a tank with starfish injected with vinegar.

This study confirms the previous findings that the weak acetic acid in vinegar is quickly diluted on the reef and poses no threat to other marine organisms. All injected CoTS die within 48 hours.

Fred Nucifora, Great Barrier Reef Marine Park Authority Director of Tourism and Stewardship, said the organisation is targeting those reefs identified as having high conservation and tourism values.

"Culling crown-of-thorns starfish is a critical management activity to protect coral cover and boost Reef resilience, particularly in the wake of coral bleaching," he said.

Bostrom-Einarsson said the method is also widely applicable to remote communities and developing countries where access to bile salts, the current substance used to kill CoTS, is limited.  — PTI