RP seas turn red as corals spawn

"The corals are spawning this week," Lory Tan pants on the Internet. "Happens only once a year, just the full moon in May. Magnificent sight. Seas, like in south of Bohol, change color in what has been described as a vast sex soup."

"Interested?" the president of World Wildlife Fund-Manila signs off with an invitation for election-weary pals to join a two-and-a-half hour drive to Anilao, Batangas, to watch the rare phenomenon.

Hours after the full moon of the 5th, colonies of male corals began squirting white sperm from reefy perches deep in the seabed. Colonies of female corals swiftly reciprocated by expelling pink, orange and red eggs. The "broadcast spawning" lasts for two weeks as the gametes float to the surface. There, in simultaneous fertilization, sperm and eggs search for mates of the same species. The blazing hue of millions of eggs, each the size of a mongo seed, turns seawaters red or, under the moonlight, bright purple. Scientists dive in for a closer look while beachcombers marvel at one of nature’s great mysteries.

But there are other, more active observers. "Filter feeders" like whales and manta ray are attracted by the pools of eggs. They move in for the feast, sucking in thousands of the organisms at a time through cartilage sieves in the mouth. Smaller predators like dulong, milky fish the size of alamang or krill, join the frenzy and nibble at the sperm. If fishermen don’t catch them quickly enough, the dulong soon become desserts of bigger fish, in a natural balancing of the ecosystem.

WWF’s Tan couldn’t waste time. He must film the feeding whales. A 30-footer was spotted last weekend in Anilao, barely 50 meters from shore. Besides, it’s now the season in Batangas of the tasty dulong, best cooked in gata (coconut milk).

Marine biologists have yet to unravel the mystery of simultaneous, precise, mass spawning of corals. One theory has to do with predators. By somehow signalling each other to secrete sperm and eggs at the same time, male and female corals are able to randomly reproduce over a large area. Whales and mantas may gobble up large numbers to their fill, but enough gametes are left to fertilize and ensure survival of the species.

Broadcast spawning also has been observed to coincide with the waning of the moon, the lengthening of daytime, the warming of seas, the ebbing of tides, and the calming of currents. Ancient mariners must have noticed waters near the shore turning red since the invention of the raft. But coral spawing was first studied up close only in the early 1990s in the Caribbean reefs. There corals spawn for three to five days, beginning on the eighth dawn after August’s full moon. Before then, spawning accidentally was "discovered" in 1982 by an underwater photographer at Australia’s Great Barrier Reef. Only last year, after the April full moon, was the event recorded at the Maldives in the Indian Ocean, where reefs were thought to be dying.

The best place to study the mass spawning is the Coral Triangle. So called because it contains more than 500 of the 700 coral species known to man, the triangle encompasses Luzon in the north, Papua in the southeast, and Borneo in the southwest. But the spawn, carried hundreds of miles off by ocean tides, are believed to have sprouted new coral colonies as far up as the southern islands of Japan, right to the northern waters of Australia, and left to the Indian Ocean.

In Tubbataha Reef north of Palawan, which contains so biodiverse a marine life that Unesco declared it a world heritage site, coral species are so varied that spawing occurs twice a year. The first is in April, according to Tan, joined the next month by coral reefs around Tawi-Tawi, Bohol and Calamianes.

In 1994 a team of ten scientists charted the Coral Triangle and found its center to be the Raja Ampat reefs, off Indonesia’s province of Irian Jaya. A spit of 22 islets inhabited by 7,700 people, Raja Ampat was said to "hold an unparalleled array of species of corals, fish and mollusks never seen before." Environment activists are working to have it declared a Unesco protected site as well.

Corals are animals from the family of polyps. That is, they are stationary and grow like stems with mouth at the tip. Some species grow in colonies that are all male, some all female, some of mixed gender. Other species are hermaphroditic, expelling both male sperm and female eggs during the mass spawning season. The gametes do not travel far, but swim just above the colony to fertilize, then settle down as "baby corals." Still others spawn not by broadcast but by brooding. Such species spit out only male gametes, soon taken in by female corals for fertilization. Inside the female grows a small planula, which is released from the mouth and drifts away to form its own colony.

Nature and man are the coral’s known enemies. Crown-of-Thorns starfish eat up reef-builders. Hot waters from El Niño or hurricanes also smother them. Man is worse, slashing thousands of corals each year with anchors, and snuffing out millions more with polluted sewerage spewing onto oceans. Global warming, caused by industrial gases, is also slow-boiling corals dead in their natural habitat.

Researching this piece, I checked out four Filipino dictionaries for a native word for coral. None! I asked why, considering that early islanders used corals for jewelry, toys, weapons or lime fortification. Writer-linguist Reuel Aguila of U.P.-Diliman explains that English had eaten up the many local terms for coral, just as Spanish replaced words for many indigenous flora and fauna. I wonder, if the local word disappeared in 400 years, how soon before corals too vanish from cyanide and dynamite fishing?

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Tune in today and tomorrow to ABS-CBN’s Election 2004 coverage, cosponsored by The STAR. Or to Hatol ng Bayan of NBN-4, RPN-9 and IBC-13, cosponsored by DWIZ (882-AM).

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