Shark study begins in Tubbataha reefs of the Sulu Sea


KORONADAL CITY (MindaNews / July 20) – A study to better understand shark behavior and population has started in Tubbataha Reefs Natural Park (Tubbataha Reefs), a protected seascape that sits in the middle of the sea of Sulu and is part of the Triangle, one of the most important reef systems in the world.

Tubbataha Reefs Natural Park has one of the highest densities of reef sharks in the Coral Triangle. In the photo, 34 juvenile gray reef sharks were seen navigating the reef. Photo by David Choy / ASEAN Center for Biodiversity

Angelique Songco, superintendent of the protected area and head of the Tubbataha Management Office (TMO), confirmed that she was conducting a shark survey given the lack of knowledge about these species in the reefs of Tubbataha, which is a ASEAN heritage park.

With support from the ASEAN Center for Biodiversity (ACB), she said the TMO, for the first time, is leading a shark survey in Tubbataha reefs following studies by the Large Marine Vertebrates Research Institute Philippines (LAMAVE) from 2015 to 2017.

“The goal is to establish trends over the years and detect changes in shark abundance and species distribution,” Songco said in a statement over the weekend.

Songco explained that the shark survey will use the Underwater Visual Survey (UVS) method, a non-invasive and unbiased approach in which divers go downstream for 40 minutes while identifying and counting sharks that pass by in a band of 30-meter imaginary transect. Although UVS has little or no effect on shark behavior, the investigation needs to be supplemented with other techniques for a better understanding of shark ecology, she added.

Researchers and marine park rangers will conduct the survey with the help of the World Wide Fund for Nature (WWF) – Philippines, LAMAVE and local volunteers.

Unfair views

Perceived as frightening and ferocious sea monsters, sharks are unfairly viewed as dangerous to humans, ACB said.

These top predators, however, play a functional role in the marine ecosystem by maintaining the balance of the food chain, thus serving as a sign of the good health of the ocean, he added.

Previous shark studies have recorded the presence of 23 species of sharks and rays in the reefs of Tubbataha, the association said.

Songco said that based on tracking the movements of tiger sharks inside and outside Tubbataha Nature Park, adults leave the park in late summer and return after a few months. ACB Executive Director Theresa Mundita Lim said the shark study, along with lessons learned and other research activities in the park, could contribute to greater efforts by stakeholders to improve shark conservation measures at national and regional levels.

Tubbataha reefs. Map courtesy of Google

“We take note of the collaborative efforts between government, non-governmental organizations and academic institutions to address knowledge gaps about sharks and other important species in the marine protected area,” she said.

According to the ACB, 254 species of sharks and rays are on the Red List of Threatened Species of the International Union for the Conservation of Nature (IUCN).

Blank site

For the Tubbataha reefs, it covers around 10,000 hectares of coral reefs in the heart of the Coral Triangle. This pristine site is home to a high density of marine species, including 700 species of fish, 13 species of dolphins and whales and more than 100 species of water birds, according to data from the Tubbataha management office.

The information generated by the study will also be used to assess the efficiency of the park’s management, with sharks being one of its key biophysical indicators, ACB said.

Shark abundance has declined in recent decades, with more than half of the 39 species now threatened with extinction, according to the IUCN.

Tubbataha Reefs are one of the last places in the Philippines where reef sharks thrive, attributed to the strict protection given to the park and sufficient area to support the movement of the supreme predator. Songco noted, however, that local and global stressors such as fishing-related activities and climate change are ever-present threats to these predators.

Amid these threats, continued monitoring of shark abundance and species distribution, complemented by other shark studies, will help inform park management and stakeholders on current trends and changes. in the overall shark ecology, she said, adding that this would further help management formulate effective shark conservation measures. (Bong S. Sarmiento / MindaNews)



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