The ‘Interim New Zealand Guidelines for Cyanobacteria in Recreational Fresh Waters’ were released by the Ministry for the Environment and the Ministry of Health in 2009. Since then, our knowledge has advanced and new issues have emerged. This report summarises literature and data published since 2009, and outlines recommended changes to the guidelines, including examples of revised alert levels and thresholds for certain types of cyanobacteria.
Further updates and research are needed to finalise the guidelines. Until the changes are finalised it is recommended that users continue to use the existing 2009 guidelines.
Cyanobacteria, which are microorganisms that conduct photosynthesis, are an important part of many ecosystems. They can multiply and form blooms under certain conditions, and some strains can produce toxins.