Philippine Scientist Grows Coral Reefs from Broken Coral FragmentsCatch of the Week
Guillermo Delos Reyes has been fishing all his life in the waters off Batangas.
Three decades ago, he could earn several thousands of pesos from fish scooped up in his nets on an overnight trip. These days, he stays out at sea for hours and returns home with a small catch, mostly juvenile fish, barely enough for two meals at home.
His story sums up the sad reality faced by most fishers, considered among the poorest people in the Philippines.
Delos Reyes’ daily income is roughly the retail value of 2 kilograms (kg) of fish, down from the average catch of 20 kg a day during the 1970s, according to a report by the Food and Agriculture Organization (FAO) of the United Nations.
Overfishing, illegal fishing methods (dynamite and cyanide), and coral bleaching due to rising sea temperatures are among the culprits cited for the declining fish catch. These have all taken a toll on the once-abundant fish stocks in the region such that the national government had to import fish to meet the requirements of the population.
If left unattended, this situation could lead to a bleak future for Filipinos. The fishery sector is essential to the Philippines. Eight out of 10 in the population rely on fish for protein sources, and some 2 million rely on the seas for jobs.
Filipinos consume at least 36 kg of fish each year or double the average per capita consumption worldwide, according to the 2013 Agricultural Outlook from the Organisation for Economic Co-operation and Development and FAO.
For most Filipino families, no meal at home is ever complete without fish. The taste and cheaper price of fish over pork and chicken makes it a preferred protein source among eight in 10 Filipinos.
The Bureau of Fisheries and Aquatic Resources (BFAR) estimates that by 2025, demand for fisheries would go up to 4.2 million metric tons annually to meet the daily needs of 134.9 million Filipinos.
To create a sustainable fisheries sector, the Philippine government is looking at creating new coral reefs. This novel, low-cost technology uses broken corals to fast-track the growth of coral reef cover by up to six times, compared to what’s called as passive coral rehabilitation that bans fishing in an area for several years.
Marine biologist Joey Gatus, an assistant professor at the University of San Carlos in Cebu, leads the national project for reef rehabilitation under a program of the Department of Science and Technology (DOST).
For a country that relies heavily on fish as food for 95 million and jobs for 2 million Filipinos, Gatus said preserving and rehabilitating coral reefs should be among the top government priorities.
Like trees that help determine productivity in forests, corals are the basic structures that form reefs. They serve as nursery to small fishes and are home to thousands and thousands of other marine life that thrives in the ocean.
The coastal water of the Philippines is a marine biodiversity center and home to 27,000 square kilometers (km) of coral reefs, which shelter more than 2,000 marine species.
Due to overfishing and destruction from the impacts of climate change, fish stocks have declined, especially in areas with poor coral reefs, leaving fisher Delos Reyes with barely enough catch to make a living.
With the goal of reclaiming the former beauty and health of Philippine seas, Gatus’ team of marine biologists uses low-cost technology to transplant corals at a cost of only P7–P25 pesos per square meter.
To do this, researchers from Batangas State University and volunteers dive and handpick coral fragments one by one from the sandy ocean bottom in Anilao and Laiya. The staghorn corals, just a few centimeters long, are broken naturally underwater. Most of the coral species they gather are antler-like branching corals such as Acropora hyacinthus, Pocillophora damicornis, and Pavona frondifera.
“Our teams dive 2–3 hours a day to collect the coral fragments from the ocean floor. This requires handling each piece of coral carefully as if you were holding puppies to prevent further stress and damage, which might result in the coral’s eventual death,” Gatus said.
Corals which are still healthy and have the ability to heal are brought to an underwater nursery.
The nursery is simple—just four poles anchored by a concrete block and connected by a mesh of nylon chords about a centimeter thick. The divers and researchers tie the corals to the nylon strings. The corals will stay there for 3 months, the average time it takes for the coral’s “wounded” portion to be covered again by polyps that serve as building blocks of a coral, Gatus said.
This process of healing is crucial to ensure that the coral fragment is healthy to be transplanted.
In the past year alone, Gatus and his team of scientists restored about 240,000 coral fragments and transplanted them to sites in Batangas and nine other pilot areas with reefs that were damaged from strong typhoons and from destructive fishing methods.
When the fragments are about the size of a fist, researchers in scuba gear dive about 40 feet underwater to reattach the fragments to stony corals.
To help fix the fragments on substrates or the hard, stony part of the coral up for rehabilitation, the team uses two methods. The cheaper, easier method requires nailing the coral fragment to the substrate using a concrete nail, while the more sophisticated method requires the use of an adhesive clay to attach the coral.
Attaching the coral with a concrete nail only costs P7 per fragment while the clay requires the team to spend P25 per application. “Both methods are effective, but using the concrete nail is the cheaper option,” Gatus said.
For the project sites in Laiya and Anilao, the group received a budget of P2 million from one of the province’s district representatives. The budget was used to buy scuba diving gear and salaries for the divers who collected and monitored the growth of the coral fragments.
Compared to passive coral rehabilitation, which includes the establishment of marine protected areas and no-fishing zones, Gatus said transplanting the coral fragments gives the reef a better head start because it uses more mature coral fragments.
“We achieved 80% survival rates using this method and that is very promising when the project goes nationwide,” he said.
Gatus noted that this average survival rate is significant given that corals as marine animals only spawn once a year, usually between the summer months of April–June.
During the spawning season, only 1% of the larvae can grow into polyps, the basic building blocks of the coral colonies characterized by their diverse colors and shapes.
Majority of the larvae released underwater will end up as food for filter-feeding fishes and marine animals. The larvae will die within 6 days if they cannot attach into a stony skeleton where colorful corals live.
How much does a healthy coral reef cost? A kilometer of a healthy coral reef cover can generate 20 tons of fishery products a year and a potential tourism revenue of $29,000–$113,000 annually—five times better than the yield of 4 tons of fish products in areas with poor coral cover, Gatus said, quoting a 1998 valuation of Philippine coastal resources.
Based on his estimate, Gatus said it would take a decade for the coral fragments to fully cover and rebuild the reefs in the project sites. On average, a healthy coral can grow up to 15 centimeters in a year.
With barely a year since the launch, many local governments with coastal communities are already expressing intent to fund and replicate the project in their areas after they saw the encouraging results of coral transplantation, he added.
Beyond the Philippines, the impact of rebuilding the coral reef cover has regional and global implications.
At the apex of the Coral Triangle, the world’s center for marine biodiversity, Gatus said making the reefs in the Philippines healthier would ensure healthy fishing population stocks that can benefit its neighbour countries and help ensure a refuge for marine life in the face of future impacts of climate change.
“Think of it this way: We rely on the seas for our survival so we are actually helping ourselves when we rehabilitate our reef cover,” Gatus said.
DOWNLOAD REPORT from the Food and Agriculture Organization of the United Nations.
DOWNLOAD REPORT from the Organisation for Economic Co-operation and Development.