marine science

Filipino scientist ushers in new era of coral restoration in the Philippines

Iya Gozum

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Filipino scientist ushers in new era of coral restoration in the Philippines

REGENERATION. Corals in Twin Reef of Port Barton spawning last May. The eggs were collected, cultured, and then released back as larvae on degraded reefs.


(1st UPDATE) Scientists are hopeful that mass larval reseeding would pave the way for large-scale restoration of coral reefs

PANGASINAN, Philippines – Off the coast of Quezon Island in Alaminos, Pangasinan, table corals are flourishing after years of restoration efforts of Filipino and Australian scientists.

The site was completely degraded before, marine scientist Dexter dela Cruz, said. But now, they are thriving.

The coral site at the Hundred Islands National Park only followed Dela Cruz’s pioneering work in a project led by renowned coral ecologist Peter Harrison.

Dela Cruz and Harrison used the sexual reproduction method or mass larval reseeding where they supplied larvae on degraded reefs at Magsaysay Reef in the Lingayen Gulf. This was the subject of Dela Cruz’s dissertation in 2013.

The study was the first in the world to successfully prove that mass larval reseeding works. It has become the springboard of coral restoration practices in the world’s biggest coral reef system, the Great Barrier Reef.

Nature, Outdoors, Water
RECOVERED. Corals thrive near Quezon Island at the Hundred Islands National Park in Alaminos, Pangasinan. Photo by Iya Gozum/Rappler

Mass larval reseeding requires scientists to work on the reef for long periods of time.

They stay at the site for nights on end, trying to catch the annual event when corals spawn – that magical mating ritual when they simultaneously release eggs and sperm into the water.

These eggs and sperms are then cultured in a hatchery in their laboratory in Bolinao, Pangasinan. The larvae are released back into the sea and on the degraded reefs through fine-mesh nets. It would take years before the tables of corals on shallow waters appear.

“Working in the reef, being in the reef for so many times just waiting for the corals to spawn, takes a lot of patience and passion,” Dela Cruz said during a briefing at the UP Marine Science Institute’s Bolinao Marine Laboratory on June 17.

Nature, Outdoors, Sea
MAGICAL. Scientists try to catch this annual event when corals spawn and simultaneously release tiny eggs and sperm into the water. This photo was taken last May in Port Barton, Palawan. Photo from ACIAR

Coral reefs are one of the most important marine ecosystems, giving shelter to fish, algae, and other species. But they have been suffering from steady degradation as oceans warm and humans continue destructive fishing practices.

For years, scientists have been working on different restoration techniques as corals bleach and reefs degrade. The predominant technique still used in coral restoration is asexual or fragmentation, where a small part of the coral is transplanted on reefs. Before that, people were building artificial reefs.

The sexual reproduction method has opened up the third era of coral restoration.

“All the scientists now are agreeing that [the] mass larval enhancement method is in the forefront now of coral restoration,” said Dela Cruz.

“Now they said we are now in a new era using [the] sexual method. And this one has the capability of restoring large areas.”

But this wasn’t always the case. In the past, this method drew skepticism from the scientific community.

Pioneering work

In 2012, Harrison linked up with Dela Cruz to test if mass larval reseeding works.

Dela Cruz designed the experiment in Magsaysay Reef in Anda, Pangasinan. They took Acropora tenuis larvae from colonies at Caniogan Reef and supplied around 400,000 larvae on degraded parts of the Magsaysay Reef. In parts of Anda, coral reefs started to decline in the 1980s amid destructive fishing and aquaculture development.

This served as a trial for Harrison’s idea that goes back to the 1980s, after he saw corals spawn in the Great Barrier Reef. The idea was that humans can intervene with the reproduction of corals, the replenishment of the reefs.

Harrison believed that mass larval reseeding could increase genetic diversity, make corals more resilient against rising temperatures, and widen the scope of restoration.

Before any large-scale efforts could be undertaken, it has to be proven first that the method works.

This became the subject of Dela Cruz’s dissertation at Southern Cross University, where Harrison served as the director of the Marine Ecology Research Center. The Australian government funded the study through the Australian Center for International Agricultural Research (ACIAR).

Summer, Clothing, Shorts
SAVING CORALS. Marine biologist Dexter dela Cruz, joined by representatives of the Australian Embassy and ACIAR, on the way to the coral restoration project site in Quezon Island in Alaminos, Pangasinan. Photo by Iya Gozum/Rappler

By 2019, when Dela Cruz finished his dissertation, the selected reef areas had recovered and looked like duplicates of the healthy reefs in Caniogan.

“We now know from the work that’s been funded by ACIAR that it is possible to restore these degraded reef systems and bring them back to [a] healthy reef system which is important for…potential food sources for the communities,” Harrison said during the briefing.

After the success in Magsaysay, scientists ventured to rehabilitate corals at the Hundred Islands National Park in Alaminos. About 18 million diverse coral larvae collected from Magsaysay Reef were released in Quezon Island in 2020. Dela Cruz said they currently have experiments in seven islands of the national park. 

Alaminos Mayor Bryan Celeste said the corals regenerated the ecosystem of the Hundred Islands.

“We saw that the ecosystem came alive because of the coral restoration project,” Celeste told reporters after a visit to the site. Aside from having rehabilitated marine resources, Celeste said the corals could be “a good tourism investment.”

“But [it] has to be managed properly,” the mayor added.

In search for the luminous whale

Snorkeling in the shallow waters near Quezon Island provides a good view of the rehabilitated corals. The area was relatively small, if one would think of how ancient, natural reefs looked before. But life is apparent. Schools of fish weave in and out of sight.

At 41, Dela Cruz had ushered in a new era of coral restoration in the Philippines.

Beyond the successful sites in Pangasinan, Dela Cruz is expanding these efforts to Batangas and Palawan, together with a team of scientists and researchers from the Marine Science Institute at the University of the Philippines Diliman (UP MSI).

For someone who is pioneering work on the Philippines’ coral reef restoration, Dela Cruz saw his first “proper” coral reef belatedly, in a trip to Tablas Strait, Romblon, after finishing his undergraduate degree in biology.

Lighting, Person, Light
NIGHT SHIFT. Scientists collect the corals’ gametes once they spawn. Photo from ACIAR

Yet he had always known that he would be a marine biologist, in a manner that must be familiar to many kids who grew up with dubbed animated series on television.

A girl, accompanied by her marine biologist father, traveled the world in search of the luminous whale. That was the plot of the series Tico of the Seven Seas, the show that introduced marine biology to Dela Cruz.

But now the work goes beyond the fascination, he said. Now it’s about the continuous search for answers – work rigorous enough to reach communities.

Will people get enough food? Will they have jobs? Will they learn to take care of their reefs and waters?

The team’s expansion to other parts in the Philippines not only restores corals, but trains academics from nearby schools to manage the rehabilitation themselves.

After he graduated from the Pamantasan ng Lungsod ng Maynila, Dela Cruz took up his masters at UP MSI.

During this time he worked as a research assistant to National Scientist Edgardo Gomez, the founding director of UP MSI. He recalled times when Gomez would make him label files of scientific journals, and then quiz him about them.

Furniture, Table, Desk
AT WORK. Dela Cruz inside his office at the Bolinao Marine Laboratory, on June 18, 2024. Photo by Iya Gozum/Rappler

The late scientist demanded nothing less than excellence. And this continues to be the standard by which many funding-strapped Filipino scientists are measured.

In a struggling country like the Philippines, scientists are not only expected to generate knowledge but to bridge the gap between institutions and communities as well.

After the briefing and the visit to Quezon Island, Dela Cruz went straight to Palawan. Earlier in June, they replenished the coral population in Port Barton and were gearing up to test the community’s readiness if they can continue the project on their own, but they had to postpone because of a coral bleaching event. They would try again next year, Dela Cruz said, when the corals are ready to spawn again.

“As an applied scientist, that’s the biggest luminous whale for me,” said Dela Cruz. “When they use your science and apply it to something good for the people.” –

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Iya Gozum

Iya Gozum covers the environment, agriculture, and science beats for Rappler.