DENR orders removal of "crown of thorns"

Environment and Natural Resources Secretary Angelo Reyes has directed all DENR regional offices to identify the coral reefs within their respective jurisdictions that are at risk or are already infested with the "crown of thorns", a kind of starfish.

In a memorandum, Reyes also instructed all DENR regional directors to organize and enlist the assistance of concerned groups and individuals in removing the noxious starfish from coral reefs.

"Identify the coral reefs within your respective jurisdictions that are at risk or are already infested with the crown of thorns," Reyes said.

The crown of thorns (Acanthaster planci) is a species of starfish that is a voracious eater of coral. A single individual can eat five to six square meters of coral per year. The starfish breeds around December to April and each female is capable of producing 60 million eggs per season.

The crown of thorns has an average size of about a foot with 10-20 arms. Its body is covered with thousands of four to five-centimeter-long poisonous spines. It is the only starfish that is known to be poisonous. This characteristic has earned for it the moniker "crown of thorns".

This starfish can be found in Mauritius in the western Indian Ocean, including the Red Sea, Australia, Ryukyu Islands in Japan, the Philippines, across the Pacific to the west coast of America.

The only known predator of adult starfish is the Triton Trumpet (Charonia tritonis), also called Pacific or Giant Triton. However, this large marine snail has been overexploited by collectors, which some say, have been responsible for the population outbreak of the giant starfish.

At its early stages of growth, however, the young of the starfish are eaten by many marine animals in and around coral reefs, most specially the Humphead wrasse (Cheilinus undulates).

It may be recalled that Reyes gave instructions for the strict implementation of laws and regulations for the conservation of this fish particularly in and around the Tubbataha Reef National Marine Park.

Reyes enjoins all concerned citizens to help in controlling and averting a population explosion of the noxious crown of thorns. "We should not wait for another calamity to befall us. With only five percent of our coral reefs in excellent condition, we can ill-afford to allow the crown of thorns to further degrade our coral reefs. We should act now," Reyes said.

Several ways of controlling the population outbreaks of the species have been devised such as with the use of poisons but the best option so far has been its manual removal from the corals. The use of thongs is recommended when prying them loose from the corals due to their poisonous spines.

There are several theories as to what cause outbreak of the crown of thorns - population fluctuations are a natural phenomenon; removal of natural predators has allowed populations to explode; and human factors such as increased nutrient run-off from land areas causing an increase in planktonic food available to the starfish larvae, causing in turn an increase in adult population.

The value of coral reefs to the Philippine economy is immeasurable. Majority of the Filipinos are dependent on fish and fisheries are dependent on coral reefs. One of the flagships of our tourism industry is scuba diving featuring the beautiful coral reefs abounding in many parts of the Philippines. As an archipelago with a very long coastline, coral reefs provide protection against erosion and they are also potential sources of medicine. - Jasmin R. Uy/MEEV