Oct 26, 2020

Tubbataha Reefs facing “serious” case of coral reefs bleaching

The coral reefs experience “stress” caused by changes in water temperature, light, or nutrient, causing them to expel the symbiotic algae living within the coral tissues, which results in the corals turning white or becoming bleached.

The water temperature in Tubbataha reached 30 to 31 degree Celsius on June, which was “too hot for the coral algae to withstand” || Contributed image by Tubbataha Management Office

 

The Tubbataha Reefs, the country’s prime and arguably most important marine protected area, is facing a “serious” case of coral bleaching caused by the unusually warm water temperature around it.

“This is the most serious I’ve seen so far,” Angelique Songco, park superintendent of the Tubbataha Reefs Natural Park (TRNP), endearingly called Mama Ranger among conservation circles, told Palawan News recently.

The coral reefs experience “stress” caused by changes in water temperature, light, or nutrient, causing them to expel the symbiotic algae living within the coral tissues, which results in the corals turning white or becoming bleached.

The Tubbataha Management Office researchers during the annual fish and coral monitoring that ran from May 26 to June 2, observed coral bleaching in Kook, Delsan Wreck, and Jessie Beazley Reefs. || Image by TMO

“It causes a shift in the composition of marine life. When we lose balance in nature, then we have a problem, and this phenomenon is beyond our control. This has happened [in Tubbataha] before, 2001, 2006, and 2017, but this is the most serious I’ve seen so far,” Songco said.

Bleaching happens when corals lose the “colorful energy-giving plants” due to high temperature, the Philippine Coral Bleaching Watch said. Marine conservationists have long blamed global warming for this phenomenon.

Normally, coral polyps live in a symbiotic relationship with the algae, which are crucial for the health of the coral and the reef. The algae provide up to 90 percent of the coral’s energy. Bleached corals continue to live but begin to starve after bleaching.

In a report published last week by the Tubbataha Management Office (TMO) based on the annual fish and coral monitoring that ran from May 26 to June 2, researchers observed coral bleaching in Kook, Delsan Wreck, and Jessie Beazley Reefs.

|| Image by TMO

On a five-point scale of the Philippine Coral Bleaching Watch, the east side of Jessie Beazley Reef and the inside of the lagoon behind the ranger station were categorized as “moderate” at Category 3, which means that certain parts were “partially bleached”.

The North and South Atolls, on the other hand, were described as “mild to moderate” at Category 1-2, that denotes certain areas were observed with patches of “white” within its coral structures. Coral bleaching was observed between the depths of two to 15 meters, with a water temperature between 30 to 31 degrees Celsius.

Corals can survive short-term disturbances, but if the conditions persist, the chances of its survival diminish, which may lead to the demise of the marine ecosystem that depends on it.

Songco believed that “nature is resilient up to a certain point”, remaining confident that the world-renowned diving site can still recover from impending doom.

“It depends on the type of corals. The first environmental principle is ‘nature knows best’. It will take its due course, and hopefully heal. We found that Tubbataha recovers relatively fast because of the steady flushing of water and marami namang panggagalingan ng larvae ng corals,” Songco added.

Saving the Seabirds

Early in July, the Tubbataha Management Office (TMO)  turned its efforts to save the sea birds of Tubbataha, by trying to revive the seabirds’ islet habitat ravaged by drought and guano overfertilization.

Songco said that they “received overwhelming responses”, after they took to social media looking for beach cabbages (Scaevola taccada) to repopulate the islets that have become “virtually flat”.

“By August, there will be a shift of personnel. We plan on sending the seedlings by then so it can still catch up with the rainy season,” Songco said.

She recalled that in 2001, the islets flourished with beach shrubs which subsequently invited some 20 red-footed boobies (Sula sula). The population ballooned to around 2,500 the following year which overwhelmed the delicate soil in the islets, causing the trees’ demise.

In May 2016, believed to be extinct for almost 20 years, a lone masked booby (Sula dactylatra) was seen nesting at the Bird Islet. After three years, on November 2019, the lone bird finally found a “partner” after it was reportedly seen hanging around the “plaza”—the unvegetated area in the middle of Bird Islet.

The islets are also a shelter to the Black Noddy (Anous minutus), an internationally protected species. The seabirds generally nest on a level platform, often created in the branches of trees by a series of dried leaves covered with bird droppings. One egg is usually laid each season, and nests are re-used in subsequent years.

“‘Yong nagbe-breed sa trees, dalawang species ‘yan—the red-footed boobies and the black noddy na internationally protected. Hindi puwedeng mawala ‘yon [black noddy] kung hindi mapapahiya tayo sa international community because it is our responsibility to protect the species,” Songco said.

The TRNP personnel and staff have also come up with several other strategies such as making temporary structures where the seabirds may nest—to a point that they also even brought dried leaves to the islets as nesting raw materials for the birds.

“That’s only one of the strategies we use. Gumawa din tayo ng structures para doon din sila mag-nest habang wala pang trees. There are so many variables we don’t understand kaya we are trying many approaches to hopefully improve the success rate,” Songco explained.

The Domino Effect

With over two decades worth of experience in conservation, Mama Ranger has called for citizens’ actions in taking care of the environment, citing the domino effect in preserving the natural wonders.

“If you’re going to think about it, the problem is both local and global because of overconsumption—the fossil fuel we keep on burning that contribute to global warming, the [single-use] plastics we use. We should be more cautious and really think that whatever we do, will always come back at us,” Songco concluded.

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