The red tide in Ma Wan has spread over Hong Kong waters, with no fish kills reported so far, the Agriculture, Fisheries & Conservation Department says.

The red tide is formed by Cochlodinium sp, which is rare in Hong Kong waters and non-toxic.

The occurrence at Ma Wan reported on May 31 still persists, and has spread to some beaches and fish culture zones. Several red tide reports were received, from June 4 to 7.

Beaches including Deep Water Bay, Repulse Bay, Middle Bay, South Bay and St Stephen's Bay, as well as Chung Hom Kok, Hung Sing Yeh and Ma Wan Tung Wan Beaches and those around Tuen Mun are affected. Fish culture zones including Ma Wan, Lo Tik Wan, Sok Kwu Wan and Tung Lung Chau are affected.

Others include Yung Shue Wan on Lamma, the East Lamma Channel, the Quarry Bay Water Front, the West Kowloon Water Front, North of Lautau, Victoria Harbour, Cheung Chau Typhoon Shelter and Lung Kwu Tan.

Red tide is a natural phenomenon. Mariculturists are urged to monitor the situation closely. The department's phytoplankton monitoring programme keeps monitoring red tide occurrences to minimise the impact on the mariculture industry and the public.

The department has also liaised with the Guangdong Ocean & Fisheries Environment Monitoring Centre regarding the recent red tide occurrences.