Red tides sighted

      Four red tides have been sighted over the past week, an inter-departmental red tide working group reported today (March 12).

      On March 5, a member of the public spotted the first red tide at Sheung Sze Wan. Staff of the Agriculture, Fisheries and Conservation Department (AFCD) spotted the second and third red tides at Tolo Channel and Port Shelter, including Ma Nam Wat and Kau Sai fish culture zones on March 8 and March 11 respectively. The fourth red tide was spotted by staff member of the Leisure and Cultural Services Department at Silverstrand Beach, Sai Kung, today.

      Apart from the first red tide, which has dissipated, the other three tides still persist. No fish deaths associated with the four red tides have been reported as of today.

      A spokesman for the working group said, "The first and fourth red tides were formed by Noctiluca scintillans, while the second and third red tides were formed by Gonyaulax polygramma. Both algae are commonly found in Hong Kong waters and are non-toxic."

      The AFCD urged mariculturists at Ma Nam Wat, Kau Sai, Kai Lung Wan, Tai Tau Chau, Leung Shuen Wan, Tap Mun, Kau Lau Wan, Sham Wan, Wong Wan, Yim Tin Tsai, Yim Tin Tsai (East), Yung Shue Au and Lo Fu Wat fish culture zones to monitor the situation closely and increase aeration where necessary.

      Red tide is a natural phenomenon. The AFCD's proactive phytoplankton monitoring programme will continue to monitor red tide occurrences to minimise the impact on the mariculture industry and the public.