Press Releases

Three red tides have been sighted in Hong Kong waters over the past week, an inter-departmental red tide working group reported today (April 17).

The first red tide was sighted by the Marine Police at the East Lamma Channel, including waters off Cyberport and South Horizons on April 12. Two more red tides were observed by members of the public on April 13 and 14 at Silver Mine Bay and from the West Lamma Channel to Victoria Harbour as well as from Ocean Park to Deep Water Bay respectively.

All the red tides dissipated today. No associated death of fish has been reported in these occurrences so far.

"The red tide at the East Lamma Channel was formed by Pseudo-nitzschia delicatissima, Pseudo-nitzschia pungens, Skeletonema costatum and Prorocentrum minimum. The one at Silver Mine Bay and from the West Lamma Channel to Victoria Harbour was formed by Pseudo-nitzschia pungens and Skeletonema costatum whereas the one from Ocean Park to Deep Water Bay was formed by Gonyaulax polygramma. All the above algal species are commonly found in Hong Kong waters. Pseudo-nitzschia delicatissima, Pseudo-nitzschia pungens, Skeletonema costatum and Gonyaulax polygramma are non-toxic. Overseas studies showed that Prorocentrum minimum may produce toxin as reported elsewhere. However, no such reports or associated fish kill have been recorded in Hong Kong," a spokesman for the working group said.

The AFCD urged mariculturists at the Cheung Sha Wan, Sok Kwu Wan and Lo Tik Wan fish culture zones 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.

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