Red tides have been sighted in Hong Kong waters over the past week, an inter-departmental red tide working group reported today (April 27).
Leisure and Cultural Services Department staff sighted a red tide at Clear Water Bay First Beach, Sai Kung, on April 24. A red flag was hoisted immediately. On April 25, mariculturists spotted red tides at Yim Tin Tsai Fish Culture Zone and Tai Tau Chau Fish Culture Zone.
All the red tides have dissipated. No associated death of fish has been reported by mariculturists so far.
"The red tide at Clear Water Bay First Beach was formed by Noctiluca scintillans while the one at Yim Tin Tsai Fish Culture Zone was formed by Heterosigma akashiwo. Both species are common in Hong Kong waters and non-toxic. The red tide at Tai Tau Chau Fish Culture Zone was formed by Ceratium furca, Ceratium tripos and Chattonella marina. Ceratium furca and Ceratium tripos are non-toxic while Chattonella marina is toxic and associated with fish kill in Hong Kong. Nevertheless, no associated dead fish was reported," a spokesman for the working group said.
Agriculture, Fisheries and Conservation Department (AFCD) urged mariculturists at Kau Sai, Ma Nam Wat, Kai Lung Wan, Tai Tau Chau, Leung Shuen Wan, Po Toi O, Tung Lung Chau, Yim Tin Tsai, Yim Tin Tsai (East) and Yung Shue Au to monitor the situation closely.
Red tide is a natural phenomenon. The AFCD's proactive phytoplankton monitoring programme will continue monitoring red tide occurrences to minimise the impact on the mariculture industry and the public.