A fighting coral fights for its life in its hometown, Puerto Galera

Puerto Galera is synonymous with a lot of things (beaches, beauties, and bars are some words that come to mind). For some reef scientists, however, Puerto Galera is also known for a coral that was first known to science in this picturesque town. The coral is Anacropora puertogalerae, an exquisite and fragile animal uncommon elsewhere in the country.

Yes, corals are animals, with each colony made up of tens to thousands of clones called polyps. Nemo and his dad lived in a giant polyp of an anemone, a close relative of corals. And like anemones (notice the underline), polyps sting to defend themselves or capture food. Nemo would have been stung if he didn’t regularly brush against the anemones’ tentacles to build up his immunity (remember a scene in the movie where Marlen was teaching his son to do this as part of his morning routine before leaving the anemone? — now you know why).

Anyway, like a lot of animals living at the bottom of the sea, corals need space. This is because space means more area to feed in (they gather food that drifts by with the currents), and gather light (for the tiny plants that they farm in their own bodies), among others. And corals fight, sometimes to the death, to get or defend space. Most people don’t notice this because often the fighting occurs at night. But at daytime, evidence of this fighting can be seen all over the reef as tissue damage among the combatants, especially in those who lost or are losing this slow-moving battle. To wage this battle, corals and their kin use a variety of weapons. Most use arms (actually tentacles) laden with special stinging cells than can inject venom. Others rely on chemical warfare, releasing toxic chemicals to harm those downstream.

Anacropora uses a unique strategy. It surrounds and besieges its adversaries and starves them to death! Because of its twig-like appearance, large fragments of the coral do break off when mature from a mother colony. Hence, the offspring is found next to its parents and given enough time, it forms patches five to 10 meters across. When patches of this coral grow too big, the ones in the middle start dying, probably because the ones that surround them have picked or filtered off the food from the water before it gets to them. This effect is most obvious when Anacropora patches, which are usually taller, reach and surround those of other corals. You will see the polyps of the besieged coral die slowly, starting from the base (where the water is most stagnant and presumably stripped of food) upwards towards the branch tips.

I recently got a chance to go back to Puerto Galera to gather data to help the municipal government and people, with assistance of a conservation NGO, set up a coastal conservation and resource management program. As the ferry entered the bay, I was heartened to find that development has not changed the landscape much over the 10 years since I had been to the area. As part of my dissertation research, I used to come here every two weeks for 18 months, making three to four dives per day for five days each time, rain or shine. This is how I learned these things I am writing here.

Unfortunately during my return, the landscape masked a deeper (relatively and figuratively) and more troubling development. Anacropora puertogalerae, the coral species first discovered here by the late Prof. Francisco Nemenzo in 1964, is disappearing from its hometown ("type locality" in scientific parlance). Many of the large patches of corals on the First and Second "Plateaus" (actually reefs in Muelle Bay) at 10- to 15-meter depth are now just rubble.

What may have happened to them? Like many things in the environment, the story will involve a number of interrelated factors. The quality of the water may have changed. Likely, it will involve the roads cut through to Sabang and the sediments carried from them by rain runoff. It will also involve the sewage from the town proper. Colleagues have already documented how, at certain times of the year, the sewage leads to blooms of an algae that smother the corals. Damage from anchors and fishing nets have been noted before, and actually incorporated in computer models that I have made. Anacropora is so fragile; you can break branch tips by just swimming over and not touching them!

So what can we do about the loss of this coral? Again, like many things about the environment, the solution will require attacking the complex problems from several directions. We (Puerto Galera residents, resort owners, boat operators, government officials, visitors, and those who have a stake in this) have to agree on a clear and transparent course of action and clear measures if we succeed at intermediate steps. At some point, a management plan will have to be agreed on (this is different from the plan of attack). Whatever it is we do, it will require concerted efforts from several sectors. Each effort should be well-focused and directed, implemented in coordination with the others. Ideally, a native of Puerto Galera should lead the effort to protect one of his own.

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WY Licuanan is a professor at the Biology Department, College of Science of De La Salle University. He is also in charge of the DLSU’s Shields Marine Station in Lian, Batangas. On his free time, he serves as curator of corals at the UP Marine Science Institute.