Previous Red Tide Occurrences

Click on the week for red tide occurrences during that period in the past month

> 2025/05/16 - 2025/05/23

> 2025/05/09 - 2025/05/16

> 2025/05/02 - 2025/05/09

> 2025/04/25 - 2025/05/02

 
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Overview of the period 2025/05/16 - 2025/05/23

No red tide was reported during this week.

Last update: 2025/05/23 noon

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Overview of the period 2025/05/09 - 2025/05/16

A red tide was sighted during the past week, an inter-departmental red tide working group reported today (May 16).

On May 10, staff of the Marine Department spotted a red tide at Victoria Harbour near Hung Hom. The red tide has dissipated. No associated fish deaths have been reported as of today.

A spokesman for the working group said, "The red tide was formed by Noctiluca scintillans, which is commonly found in Hong Kong waters and non-toxic."

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.

Please click here to view the location of red tide sighted in Hong Kong waters.

Last update: 2025/05/16 noon

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Overview of the period 2025/05/02 - 2025/05/09

A red tide was sighted over the past week, an inter-departmental red tide working group reported today (May 9).

The red tide was spotted by staff of the Leisure and Cultural Services Department on May 2, at Silver Mine Bay Beach, Lantau Island. The red tide has dissipated. No associated death of fish has been reported.

A spokesman for the working group said, "The red tide was formed by Heterosigma akashiwo, which is commonly found in Hong Kong waters. According to literature overseas, the algal species can produce neurotoxins and kill fish by damaging their gills."

The Agriculture, Fisheries and Conservation Department (AFCD) urged mariculturists at Lo Tik Wan, Sok Kwu Wan, Ma Wan and Cheung Sha Wan fish culture zones to monitor the situation closely and increase aeration where necessaryy.

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.

 Please click here to view the location of red tide sighted in Hong Kong waters.

Last update: 2025/05/09 noon

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Overview of the period 2025/04/25 - 2025/05/02

A red tide was sighted over the past week, an inter-departmental red tide working group reported today (May 2).

The red tide was spotted by staff of the Environmental Protection Department on April 25, at Tolo Harbour including Yim Tin Tsai fish culture zone. The red tide has dissipated. No associated death of fish has been reported.

A spokesman for the working group said, "The red tide was formed by Gonyaulax polygramma, which is commonly found in Hong Kong waters and non-toxic. "

The Agriculture, Fisheries and Conservation Department (AFCD) urged mariculturists at 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.

Please click here to view the location of red tide sighted in Hong Kong waters.

Last update: 2025/05/02 noon

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