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A Cheap Pantry Ingredient Can Wipe Out 100% of Coral-Eating Starfish

Vinegar FTW.

FIONA MACDONALD
23 SEP 2015
 

Household vinegar is already used to make kick-ass salad dressings, clean bathrooms, and soothe insect bites, and now Australian scientists have shown that it can also kill the Crown of Thorns Starfish (CoTS) - which is currently munching its way through the Great Barrier Reef - with a 100 percent success rate.

 

The CoTS is a spiny species of starfish that feasts on live coral, and it's currently breeding at epidemic levels on Australia's Great Barrier Reef. Research suggests that the starfish are already responsible for almost half of the decline in the reef's coral cover, and the only weapon scientists have to control them is to inject them with a special drug. But while it's effective at culling the starfish, it can be expensive and difficult to source.

Now a new study by James Cook University scientists suggests that using cheap household vinegar is just as effective at wiping out the animals. “Currently divers use 10 or 12 ml of ox-bile to kill each CoTS," lead researcher Lisa Boström-Einarsson said in a press release. "It’s expensive, requires permits and has to be mixed to the right concentration. We used 20 ml of vinegar, which is half the price and can be bought off the shelf at any local supermarket.”

The researchers found that the vinegar killed all of the starfish within just 48 hours of being injected, and so far in lab trials there have been no ill effects detected in the fish that ate their dead bodies. However, she admits that additional studies are needed to confirm that this is the case.

"There’s no reason to think it won’t work or it’ll be dangerous, but we have to be sure," she said.

The research is particularly exciting for developing countries that don't currently have the budget to purchase the CoTS drug, but need to do something to protect their corals.

The downside is that while the vinegar shows great potential at wiping out CoTS, the researchers admit that killing individual starfish is never going to be enough to save coral reefs. But for now, it's the only weapon we have to help slow their growth. 

“It has been estimated there are between 4 and 12 million of the starfish on the Great Barrier Reef alone and each female produce around 65 million eggs in a single breeding season," said Boström-Einarsson. "[Scientists] managed to kill around 350,000 last year with two full-time boat crews. While it would take an insane effort to cull them all that way, we know that sustained efforts can save individual reefs." 

Other research groups are now working on population-level control techniques. And a team of researchers at Queensland University of Technology has even developed an automated Terminator-like underwater robot, that swims around injecting any CoTS on sight. It's already capable of killing way more starfish than a diver can.

The next step is for the James Cook University group to begin trials with vinegar and wild CoTS on the Great Barrier Reef - something they aim to do this by the end of the year. Then hopefully someone will hook those starfish-killing robots up with some vinegar in their needles, because we're pretty sure that would be unstoppable.

The results of the study have been published in the Journal of the International Society for Reef Studies.

Find out the latest coral reef research over at James Cook University.

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