Unmonitored tourism-related activities such as diving and snorkeling have been degrading the coral reef ecosystem in the world-famous Boracay beaches over the past two decades, a Japanese-funded study said.

In a five-year study called the Coastal Ecosystem Conservation and Adaptive Management, which was conducted from 2010 to 2015, the Japanese International Cooperation Agency (Jica) said coral cover in Boracay declined by 70.5 percent from 1988 to 2011.

Through analyzed satellite images, the study also noted that the highest decrease in the 23-year period was recorded in recent years from 2008 to 2011 when tourist arrivals went up by 38.4 percent.

“We hope that LGUs (local government units) and policy makers will be able to use scientific and tecnological knowledge to address critical environment issues affecting the study’s pilot sites,” said Jica senior representative Takahiro Morita in a statement.

Filipino scientist Miguel Fortes from the University of the Philippines, who contributed to the study, said water quality in the eastern part of the island has been detoriating, making it “unsafe” for swimming and other activities.

Fortes said the direct discharge of untreated water along the shore may result in coral reef deterioration and algae formation.

Another UP scientist Ariel Blanco said the Boracay ecosystem should not be sacrificed for economic goals, urging authorities to act immediately to prevent further damage.

“It’s very crucial that the sustainability of Boracay’s environment will not be exchanged for short-term economic gains,” Blanco said. “We hope to continue working with planners and policy makers in the island through knowledge sharing that will help conserve the coastal environment.”

Jica has also installed closed circuit television cameras in the area to monitor reported sand erosion, which has been damaging Boracay’s famous white shoreline.

The study said corals play an important role in protecting the beach from erosion by reducing the impact of the waves.

“Tourism is an important economic driver in the Philippines. By protecting marine resources, we are also helping sustain the tourism industry, and jobs creation in the country,” Morita added.