Four red tides have been sighted in Hong Kong waters in the past few days, the inter-departmental red tide working group said today.

Environmental Protection Department staff saw a red tide at the south of Lantau Island on June 11, and Government Flying Service staff and the public observed one at Tai Long Wan and Po Pin Chau on June 16.

Both red tides dissipated the following day.

Turtle Cove Beach closed temporarily

Leisure & Cultural Services Department staff saw one at Shek O Beach on June 16 and another at Turtle Cove Beach this morning. The red flag was hoisted at the two beaches. The red tide at Shek O Beach dissipated the following day. Turtle Cove remains closed until further notice.

The red tide at the south of Lantau Island was formed by Chaetoceros socialis which is seldom found in Hong Kong waters and is non-toxic.

The other red tides observed were formed by Trichodesmium erythraeum which is also seldom found in Hong Kong waters.

Though this red tide has been reported to cause itching and burning upon skin contact, this kind of reaction has not been recorded in Hong Kong, the working group said.