On December 27, 2024, the Inter-departmental Red Tide Working Group revealed some unsettling news for Hong Kong's marine environment: in just one week, a staggering nine red tides have been detected in the waters around the city. The initial three sightings were made on December 21 at Lido Beach, Casam Beach, and Ting Kau Beach in Tsuen Wan by vigilant staff from the Leisure and Cultural Services Department (LCSD).

As the week progressed, on December 23, two more red tides were identified in the typically serene areas of Deep Bay and Tai Lam Chung by Marine Department personnel. The situation worsened as the LCSD reported two additional occurrences on December 26 at Ma Wan Tung Wan Beach and Kwun Yam Beach in Cheung Chau. The latest distressing reports on December 27 saw the Environmental Protection Department and the Agriculture, Fisheries and Conservation Department (AFCD) discovering two more red tides in the iconic Victoria Harbour and beautiful Discovery Bay.

Currently, red tides continue to impact several locations, including Deep Bay, Tai Lam Chung, Kwun Yam Beach, Victoria Harbour, and Discovery Bay, while four of the previously detected tides have dissipated. Fortunately, as of now, there have been no reported fish deaths attributed to these red tides.

A spokesperson for the working group indicated that the red tides at Kwun Yam Beach and Discovery Bay were caused by the non-toxic species Noctiluca scintillans, which is often found in local waters. However, the other seven red tides were linked to Phaeocystis globosa, a species known for generating foam that can adversely affect fish—a concerning fact based on overseas research.

In light of these developments, the AFCD has urgently urged mariculturists in the Ma Wan and Cheung Sha Wan fish culture zones to remain vigilant and enhance aeration measures to help protect marine life.

Red tides are a natural phenomenon, but their environmental impact can be serious. The AFCD’s proactive monitoring of phytoplankton will continue to be essential in tracking red tide events, thereby mitigating their consequences for both the mariculture industry and public health.

As awareness grows, the community is left wondering: will these red tides pose a long-term threat to Hong Kong's rich marine biodiversity? Stay tuned for updates as the situation develops!