In an “astonishing” discovery, two scientists in Queensland found that the protein mixture triggers an acute allergic reaction and causes the crown-of-thorns starfish to break apart and die within as little as 24 hours.
Scientists have been struggling to prevent further damage by the starfish along Australia’s famous Great Barrier Reef, which has lost half of its coral cover in the past 27 years. The starfish have been blamed for more than 40 per cent of that loss – and they can damage up to 90 per cent of a reef’s coral. Recent outbreaks have been reported in the Barrier Reef, as well as Guam, French Polynesia, Papua New Guinea, and the central Indian Ocean. A female can release more than 50 million eggs a year, though the survival rate is usually low.
Researchers at James Cook University in Queensland made the breakthrough after examining a bacteria which occurs naturally in the starfish.
In what has been described as a “Eureka moment”, one of the scientists, Dr Jairo Rivera Posada, was conducting research on an island in the Barrier Reef and wondered whether a substance being used to culture the bacteria could give the bugs enough of a boost to damage their host. He and his colleague, Professor Morgan Pratchett, injected five starfish with the solution – made from carbonates and proteins extracted from animal tissues – and were “astonished” as the starfish rapidly began to fall apart.
“I was only hoping to impair their immune systems – so the fact that they died so quickly was a great surprise,” Dr Posada said.
The researchers found the solution caused the bacteria to bloom and attack the starfish – and simultaneously the starfish suffered an acute allergic reaction to the unfamiliar animal proteins.
Dr Posada said the next step will be to show the protein is safe for other marine life but the mixture could potentially prove far more effective than current methods for controlling outbreaks, such as using divers to repeatedly inject the starfish with poison at targeted sites. The solution would need only a single jab and could enable a diver to kill as many as 500 starfish in a single dive – compared with 40 using the poison.
However, the new weapon is unlikely to be ready to prevent the current outbreak, which has been rapidly destroying coral across the Pacific and Indian Oceans.
“A crown of thorns outbreak can destroy from 40 to 90 per cent of the corals on a reef and over the past 50 years it has caused more damage than bleaching,” Dr Posada said.
“In the current crown of thorns outbreak in the Philippines they removed as many as 87,000 starfish from a single beach. This gives you an idea of the numbers we have to deal with.”