Suchana Chavanich, of marine science department, Faculty of Science, wrote in her Facebook that she was shocked and disheartened during a recent dive at Koh Chan to check on the seven-year-old table corals which were about 15cm long.

“Most of them have gone mysteriously missing. There are no pieces of the corals in the area. Maybe somebody took them,” she wrote.

She described the corals on the reef as healthy. She plans to meet nature park officials on Thursday to discuss the issue.

She posted photos of the area that showed before and after the corals went missing.

Koh Chan is a protected zone under the jurisdiction of the Navy that has a base there.

“I already talked to officials who told me that they are investigating the issue. Tomorrow we may know where and how the corals went missing,” she said.

This is the first time that corals have disappeared from the reefs, which were made from cement structures.

She said she was surprised to learn about the disappearance as the area is under the jurisdiction of the Navy and she has never seen tourists or fishing boats there. “However in the past few years, I saw some fishing boats enter the area and I do not know how they could do that.”