Warnings and Alerts

Active warnings and alerts for Canterbury region

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  Toxic algae warnings for cyanobacteria in rivers

  22 DEC 2025 By ENVIRONMENT CANTERBURY (SK)

  HEALTH WARNING UPDATE ISSUED BY THE NATIONAL PUBLIC HEALTH SERVICE The National Public Health Service have issued a health warnings for toxic algae. The warnings follow detection of moderate to high cover of toxic algae (benthic cyanobacteria) in the:  Waihao River at Gum Tree Flat Rd (Don'...
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  Lake Pegasus cyanobacteria warning

  10 DEC 2025 By ENVIRONMENT CANTERBURY (SK)

  Issued 10 December 2025: Health Warning – Algal Bloom in Lake Pegasus The National Public Health Service has issued a health warning after potentially toxic harmful blue-green algae (planktonic cyanobacteria) was found in Lake Pegasus   People should avoid the Lake and animals, particu...
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  Te Waihora/Lake Ellesmere cyanobacteria warning

  5 MAR 2024 By ENVIRONMENT CANTERBURY (GR)

  Update March 2024: Due to the high biomass of cyanobacteria in the lake the health warning is still current. 8 February 2022 to date Canterbury DHB’s Community and Public Health unit has issued a health warning after potentially toxic blue-green algae (planktonic cyanobacteria) was found in Te Waiho...
• Lake Rotorua - permanent cyanobacteria health warning

  6 MAR 2023

  Long term water testing indicates that there is a regular bloom of the potentially toxic cyanobacteria Anabaena and/or Microcystis present. There is a permanent health warning advising people to avoid contact with water at this lake. Environment Canterbury continues to monitor the lake on a regular...
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  St Annes Lagoon/Mata Kopae cyanobacteria warning

  7 JUL 2022 By ENVIRONMENT CANTERBURY

  Permanent Health Warning for Algal Bloom at Mata Kopae/St Anne’s Lagoon. Issued: 7 July 2022 Long term water testing indicates that potentially toxic cyanobacteria bloom periodically in Mata Kopae/St Anne’s Lagoon. There is a permanent health warning advising people (and animals) to avoid contact wi...