Okinawa corals suffer bleaching

The Yomiuri Shimbun

12:42 JST, August 23, 2022

Coral bleaching was recently confirmed off Iriomote and Ishigaki islands in the Yaeyama Islands of Okinawa Prefecture, home to many coral reefs.

Coral bleaching occurs when zooxanthella, a type of phytoplankton, loses its pigments or escapes from the coral with which it usually coexists.

If the condition worsens, the coral can die off due to the lack of the nutrition normally supplied by zooxanthella. Higher sea temperatures are believed to be among the reasons behind the bleaching.

“As no typhoons have approached the area around the islands this year, sea temperatures might have remained high for lack of churn,” said coral ecology expert Takashi Nakamura, an associate professor at the University of the Ryukyus.

The Environment Ministry and the university plan to conduct a field survey in the area as early as September.