The Agriculture, Fisheries & Conservation Department urges fish farmers to keep a close watch on their stocks due to the recent spate of red tide occurrences in Hong Kong waters. They should report any fish kills or irregularities to the department, which is monitoring the situation.

Red tide has been reported at beaches on southern Hong Kong Island and in Tuen Mun, as well as fish culture zones in Ma Wan, Lok Tik Wan and Sok Kwu Wan in recent days.

Yellow flags are being hoisted at affected fish culture zones and operators have been advised to start aeration at night and monitor the situation. The department has also stepped up its proactive phytoplankton monitoring programme.

The algae that formed red tides in those areas is Cochlodinium sp, which is non-toxic and rare in local waters, with only two occurrences between 1997 and 2006.