Crown-of-Thorns Starfish outbreak devastating Philippine Reefs

28/04/2007 00:00:00 April 2007. A serious infestation of Crown-of-Thorns Starfish (Ancanthaster planci) can decimate entire sections of coral reef in weeks. A single COT can consume six (6) meters of healthy reef in a year. This year the COTS have returned – in ever greater numbers. Outbreaks have been reported on many Philippine reefs, including Mabini, Batangas, Apo Reef and Puerto Galera in Mindoro, Roxas in Palawan, Bolinao in Lingayen Gulf, Kiamba and Glan in Sarangani Bay. It is possible that many other coastal areas have been affected as well.

Each summer, whenever ocean temperatures and nutrient levels increase, giving rise to algal blooms, many Philippine reefs experience COT outbreaks. Major predators that should, under normal conditions, keep COT populations in check, have suffered from the intense pressures of population and fishing.

Overfishing is the problem
Among these predators are several Wrasse species (including the Napoleon Wrasse or Mameng), the Giant Triton (Charonia tritonis) and coral polyps themselves - all of which are steadily declining due to illegal collection for the food and aquarium trade.

Normally, reefs should be left alone to deal with unusual occurrences such as this. However, the situation facing Philippine reefs is far from normal. We once had 25,000 square kilometres of coral reef. A recent World Bank study reveals that barely 1% remains pristine and more than 50% are unhealthy. This vacation season, WWF-Philippines urges everyone going to the beach to help clean up COT infestations – to minimize local damage and support the rehabilitation of our ailing coral reefs.

Organizing COT Clean Ups
‘When diving or snorkelling, look for conspicuous portions in healthy coral heads worn white,’ says WWF Media Officer Gregg Yan. ‘Nearby you should be able to spot a COT, which looks like a cross between a sea urchin and a large grey starfish.’

‘Do NOT touch it,’ warns WWF CEO Lory Tan. ‘A COT’s long spines are capable of severe stings. Contact will almost surely inflict severe swelling, pain and nausea that can last for hours or days, so be extremely careful.’

WWF advocates the proper method of collecting and disposing of COT Starfish. ‘Using Tongs, or anything similar, gently pry the COT from the coral head or rock face. Do not cut it up, for its constituent parts may live on. Place all collected COTS in a bucket or holding bin - then dispose of them humanely on the beach,’ says Tan.

WWF has already organized numerous COT clean ups, the most recent of which netted out hundreds of COTS last February at Apo Reef. ‘We have to act now, and not when summer is over – and the damage has been done,’ says Tan. Ultimately, the best response it to keep the reef healthy, stop overfishing, manage sewage and agricultural runoffs, and promote balanced reef biodiversity.