Press Releases

Four red tides have been sighted in Hong Kong waters over the past week, an inter-departmental red tide working group reported today (April 11).

Three red tides at fish culture zones within Tolo Harbour, Sha Tau Kok fish culture zone and Tai Mei Tuk were observed by staff members of the Agriculture, Fisheries and Conservation Department (AFCD) during April 8 to 10.

Another red tide was spotted on April 9 by a member of the public at Pak Sha Wan, Sai Kung.　

All the red tides still persist but no associated death of fish has been reported in these occurrences so far.

"The red tides at fish culture zones within Tolo Harbour and Tai Mei Tuk were formed by Gonyaulax polygramma, Prorocentrum minimum and Heterosigma akashiwo. The one at Pak Sha Wan, Sai Kung, was formed by Gonyaulax polygramma whereas the one at Sha Tau Kok fish culture zone was formed by Heterosigma akashiwo and Prorocentrum minimum. All the above algal blooms are commonly found in Hong Kong waters. Gonyaulax polygramma and Heterosigma akashiwo 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 Yim Tin Tsai, Yim Tin Tsai East, Ma Nam Wat, Yung Shue Au, Lo Fu Wat, Kai Lung Wan, Sha Tau Kok, Ap Chau, Kat O, O Pui Tong, Sai Lau Kong, Tap Mun, Kau Lau Wan, Wong Wan and Sham 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.

Ends