Crown of Thorns – a wily and resilient opponent

COTsTHE Crown of Thorn starfish (COT) – one of the major dangers to coral reefs in the Pacific – may be a more resourceful and therefore dangerous entity than was originally considered, says a respected New Caledonian scientist.

Dr Pascal Duma, a leading Pacific expert on COTs, said anecdotal evidence was mounting that COTs not only moved in large numbers but appeared to have organised ‘forward scouts’.

“It is as though they are sniffing out fresh coral as they lead the group on and they also appear to be alert to any dangers their group may encounter,’’ he said.

Speaking at the Wahoo Bar and Restaurant to a large group of Havannah Harbour residents, who are fighting the COTs in a community led battle in their own waters, Dr Duma said it also appeared that after large groups of COTs were destroyed they quickly retreated to deeper water.

“It seems they head down as far as about 30 metres in an organised effort to escape their attackers,’’ he said.

The meeting heard from anti-COTs campaigners, accountant and diver John Warmington and veteran crusader Peter Whitelaw, about the most successful methods of destroying this marine monster.

A diver collecting COTs with a hook and sack.
A diver collecting COTs with a hook and sack.

Peter explained that using a metal prod with a hooked end and simply stuffing the COT into a flour bag then tying it off for removal 24 hours later was the most cost effective method he had seen.

John and his team have been using Australian-made injection kits filled with vinegar to kill the COTs in situ.

Demonstration of how the injection kits are used.
Demonstration of how the injection kits are used.

Dr Duma said not only did two injections ­– each of 10ml of vinegar – quickly killed the COTs but they had discovered that the vinegar deactivated the COTs’ eggs.

“It is 100 per cent effective and kills the COTs in less than 24 hours, then other fish devour the remains,” he said.

The meeting heard that at one site in Havannah, residents found a number of COTs that had been cut in half by villagers with bush knives, thinking this would kill them.

“In fact they mutate, so the villagers were actually multiplying them and they must be educated about how to properly destroy them,” he said.

“They must understand that if the COTs destroy their coral reefs, there will be no food for them for the next 30 years or more until the coral regenerates.’’

Rocky Kaku from the Vanuatu Fisheries Department who also attended the meeting said they were looking at ways of educating the villagers around coastal Efate about COTs, perhaps through schools.

Dr Duma said introducing large numbers of the COTs’ natural predators like tridents and trigger fish would be counterproductive, as they destroy other marine life as well.

John and Peter vowed to continue the fight against COTs ­– with community support.

“We will win, we will beat them,” said John with conviction.