Taiwan: Unusual coral bleaching reported off Yehliu coast

Bleaching in Taiwan has mainly been reported in the south, but ocean temperatures off New Taipei City rose to 33°C, a 15-year record, an expert said
Lin Chia-nan Taipei Times 17 Sep 18;

Many clusters of coral off the northern coast have bleached due to higher seawater temperatures this year, an unprecedented occurrence in the area, Academia Sinica researcher Allen Chen (陳昭倫) said yesterday.

The large-scale coral bleaching documented off the coast of Yehliu (野柳) in New Taipei City’s Wanli District (萬里) is unusual, given that the area is generally considered a “shelter” for coral, with a relatively low seawater temperature of 27°C to 28°C in summer, he said.

A researcher at the institution’s Biodiversity Research Center, Chen and his laboratory members have monitored coral in the area since 2000.

Coral bleaching is caused by rising water temperatures and can be fatal for coral, Chen said.

Coral bleaching incidents in Taiwan have previously occurred at lower latitudes, such as off Kenting (墾丁) in Pingtung County, Green Island (綠島), Orchid Island (Lanyu, 蘭嶼) and the Pratas Islands (Dongsha Islands, 東沙群島), where the seawater is warmer, he said.

The average seawater temperature at 3m depth off Yehliu was 27.38°C from May to August in 2005, but in the same period this year, it was 28.36°C, Chen said.

The temperature last month even rose to 33°C, a 15-year record, he said.

“Even a 0.5°C temperature increase can make coral sick,” Chen said, adding that reefs at higher latitudes are more sensitive to warming.

Researchers found that 11 types of stony coral and soft coral in the area had bleached, with lace coral and hood coral most seriously affected, he said.

The bleaching might reverse as the weather becomes cooler and his team would keep monitoring the corals to see whether they show any signs of recovery, Chen said, adding that the team would publish its findings.

In related news, the coral off Pingtung has been reported to be more muddy than usual, with senior diving instructor Tsai Yung-chun (蔡永春) saying that he has never seen so much sediment in the area.

The Kenting National Park Management Office on Friday said that the mud was washed offshore by heavy rain last month, but would be swept away by sea currents.

The office said it would conduct an underwater inspection after the weather stabilizes and would continue to monitor land conservation efforts in neighboring areas.

Additional reporting by Tsai Tsung-hsien