Researchers at Australia's James Cook University have found a cheap and readily available antidote for the plague of reef-eating starfish invading the Great Barrier Reef.

Vinegar, scientists say, works just as well as conservationists' current weapon of choice, a drug that's expensive and hard to procure.

In recent years, populations of crown-of-thorns starfish (COTS), Acanthaster planci, have grown -- threatening Australia's coastal ecosystems. Expanding colonies suck nutrients from the resident coral and overwhelm the reef. Some estimates place 40 percent of the Great Barrier Reef's decline on the invertebrate's overabundance.

"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," Lisa Bostrom-Einarsson, a marine biologist who helped test the new treatment, said in a press release. "They 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."

Currently, teams of divers are working to eradicate the invading starfish by injecting the creatures, one at a time, with ox-bile -- a solution that's costly and inconvenient.

Thankfully, Bostrom-Einarsson and her students found that a basic vinegar solution serves as a perfectly suitable replacement, with a 100 percent kill rate.

Fish that fed on the vinegar-injected starfish showed no ill-effects, but researchers will have to conduct a larger trial before the vinegar antidote is tested out in the ocean.

Researchers are looking into broader population-control strategies, but currently, taking out the starfish one by one is the only suitable mechanism for slowing the echinoderms' advance.

By the time the new solution is ready to be used in the sea, it may be carried and injected by a robot. Researchers at the Queensland University of Technology are currently testing an autonomous underwater robot programmed to take out invading starfish.