The first red tide was spotted by staff of the Leisure and Cultural Services Department at Repulse Bay Beach on 1 September. The red flag was hoisted at the beach immediately. The red tide has dissipated already.
Another red tide, which was spotted by staff of the Agriculture, Fisheries and Conservation Department (AFCD) at Yim Tin Tsai East Fish Culture Zone on the 4 September, still persists.
No associated death of fish has been reported in these occurrences so far.
"The red tide at Repulse Bay Beach was formed by Noctiluca scintillans and the one at Yim Tin Tsai East Fish Culture Zone was formed by Haematococcus pluvialis. The former is commonly found in Hong Kong waters while the latter is less common, and both are non-toxic," a spokesman for the working group said.
The AFCD urged mariculturists at the Yim Tin Tsai, Yim Tin Tsai East, Yung Shue Au, Lo Fu Wat, Sok Kwu Wan, Lo Tik Wan and Po Toi 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.
