Human activities have also played a big role in the decline of the coral cover on Liuqiu, a coral island that lies about 15 kilometers off Taiwan's southwest coast and is part of Pingtung County, the experts said.

This is evident in recent measurements of the coral cover, the proportion of a reef surface covered by live stony coral — in the island's diving and non-diving zones, said Fan Tung-yung (樊同雲), a research fellow at National Museum of Marine Biology & Aquarium in Pingtung County. The coral cover ratio in Liuqiu Island's non-diving zones ranges from 6.5 percent to 31.8 percent, while in the areas where diving is allowed it is 0.3 percent to 5.5 percent, he said in January at an NGO conference on the environment on Taiwan's outlying islands.

"Due to over-fishing and tourism activities, as well as typhoons and heat waves, the seabed off the island has become barren and polluted, and only sea turtles can been seen there now," Fan said. "The coral reefs near Liuqiu Island are now either degraded or disabled and are in worse shape than those in other parts of the country."

Based on global standards, Taiwan's Ocean Conservation Administration (OCA) categorizes the condition of coral reefs as either healthy, stable, degraded or disabled. Now deemed as disabled, Liuqiu's intertidal zone, the shoreline area between the high tide and low tide marks, has gone from being a major tourist attraction to a problem site in dire need of remedial actions, the OCA has said, citing research it carried out in 2021 on 62 coral reef sites across Taiwan.

The findings, released in January this year, indicated a rapid decline in the health of Liuqiu's corals since 2020, when a similar study had found that the island's coral reefs were among the healthiest across the country, the OCA said. Live stony corals are the main contributors to a reef's three-dimensional framework, the structure that provides a critical habitat for many organisms, according to scientists.

Corals, in both tropical and temperate regions, host about 25 percent of the world's marine species and are vital to the sustainability of other ecosystems, scientists have said. Of the 700 species of stony corals identified worldwide, 250 can be found around Taiwan, according to the international environmental organization Greenpeace.

Taiwan's corals, however, are in crisis, particularly after suffering massive bleaching in 2020 as a result of the worst heat stress in the country in decades, which resulted from global warming and a low incidence of typhoons in the country that year, experts said. Liuqiu Island was the area hardest hit by the extensive coral bleaching, which now threatens biodiversity around the island, scientists said.

In light of the dire situation, Fan said, the Taiwan government needs to take urgent action, such as restricting the number of visitors to Liuqiu and creating a conservation zone to allow for the revival of the endangered marine species there. At the recent NGO conference, Ho Tsung-hsun (何宗勳) said the Taiwan Citizen Participation Association, which he heads, is scheduled to meet with President Tsai Ing-wen (蔡英文) on April 22, international Earth Day, to discuss the coral crisis.

"We hope to bring the government's attention to the issue and seek action that will revive the coral reefs around Liuqiu Island," Ho said.

Days after the conference, the OCA issued a statement, saying it had been monitoring the health of the coral reefs around Taiwan since the 2020 bleaching event. The agency said it planned to launch a project this year for the revival of marine species and will conduct a comprehensive analysis of 100 coral reef sites around Taiwan, in cooperation with institutions such as Academic Sinica, National Taiwan University, National Taiwan Ocean University, and National Museum of Marine Biology & Aquarium.

Meanwhile, on Liuqiu Island, while its vibrant tourism revolves around its marine attractions, some balance would have to be found in order to protect those valuable assets, the OCA said. With that in mind, restrictions will be imposed on public visits to intertidal zones designated by the Pingtung County Government as conservation areas, with effect from April 1, the OCA said.

In addition, a full fishing ban in such areas is being considered, to allow for the revival of giant clams and other marine species and restoration of the rich biodiversity in Liuqiu Island's waters, the OCA said.