WWF, DENR join forces to stop predator starfish

By Alex Villafania
INQUIRER.net

THE WORLD Wildlife Fund Philippines and the Department of Environment and Natural Resources are working together to save the country’s vast coral reefs against the predatory crown-of-thorns starfish (Acanthaster planci), which feeds on living coral.

Just recently, over 5, 212 crown-of-thorn starfishes were caught off the vicinity of Apo Reef in Sablayan, Occidental Mindoro, which has been devastated by the predatory animals.

Crown-of-thorns are found throughout the Indo-Pacific region and these could grow to 80 centimeters in diameter. These large creatures are so named for their stingy thorns that coat their bodies. When fully grown, a group of crown-of-thorns can decimate in just a few weeks several square meters of coral, which need years to grow. Just one adult crown-of-thorn can consume six square meters of coral in a year.

While the crown-of-thorn starfish seems unstoppable, it has natural predators such as the Napoleon Wrasse, Harlequin Shrimp and Giant Triton. However, global fish stocks have been over-harvested since the 1950s — the World Fish Center estimates that as much as 90 percent of the world’s fish stocks have been consumed.

The DENR and WWF began removing crown-of-thorns in Sablayan since early this year but previous attempts collected less than 3,000, even with the help of some locals. It was during the last summer season that they saw a boom in crown-of-thorn population, which normally happens during this season.

On the other hand, WWF said in a statement that it is not completely removing the crown-of-thorn population but merely controlling their population explosion. WWF CEO Lory Tan said that generally, Philippine reefs are not healthy or are still recovering and crown-of-thorn starfishes help in preserving the population of corals, some of which also grow very fast, which can in itself damage the ecological balance.

WWF Asia Pacific energy policy coordinator Raf Senga said the factors contributing to the crown-of-thorn population boom is the increase in ocean temperatures brought about by climate change.

“Higher water temperatures cause algal blooms that provide excess food for corals, the primary predator of young larval starfish. Consider the fact that one COT can lay up to 60 million eggs. If just 1 percent survives, then figures will tell us that 600,000 can be generated from a single parent. Alter just a few factors and their survival rate increases — a difference of just one degree centigrade might have colossal consequences for all Philippines’ reefs. This in addition to coral bleaching caused by abnormally warm sea temperatures that have been observed during El Niño events,” Senga warned.

The group is calling for volunteers to join their clean up drives for Apo Reef. Announcements and registration for volunteers can be done through the WWF Philippines website.

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