| 17 May 2023

Health Warning lifted for Algal Bloom in in Saltwater Creek (Ōtipua)

Te Mana Ora | Community and Public Health has lifted its algal bloom health warning issued for the Saltwater Creek (Ōtipua). This was issued on 9 January 2023.

Recent cyanobacteria surveys of the Saltwater Creek (Ōtipua) has shown the amount of potentially toxic algae (planktonic cyanobacteria) in the river has reduced and is now below levels that are of concern to public health.

Dr Cheryl Brunton, Medical Officer of Health for Te Mana Ora, National Public Health Service Te Whatu Ora, says Environment Canterbury’s monitoring of Saltwater Creek (Ōtipua) will resume next summer when there is increased likelihood of cyanobacteria growth.

The warning to avoid the following waterway due to ongoing algal blooms is still in place:

  • Lake Opuha.

Facts about cyanobacteria:

  • A low cover of the algae can occur naturally but can increase rapidly during warmer months. Algal blooms are influenced by a combination of available nutrients in the water and sediments (such as nitrogen and phosphorus), a sustained period of low and stable flows, and favourable weather conditions (e.g. increased temperature, calm days)
  • If the water is cloudy, discoloured, or has small globules suspended in it, avoid all contact
  • It often has a strong musty smell and algal toxin concentrations can vary over short periods
  • Although high river levels will remove the algal bloom, detached mats can accumulate along the shore and increase the risk of exposure to toxins
  • If a health warning is in place avoid contact with the water
  • Exposure to an algal bloom can cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips. If you experience any of these symptoms visit your doctor immediately and please let your doctor know if you have had contact with lake water when there is a health warning in place
  • Although district or city councils may place warning signs, these may not be seen at the numerous river access points, hence the need for people/ dog-walkers to treat every low-flowing river cautiously.

For further details visit: https://www.lawa.org.nz/explore-data/canterbury-region/

Or contact Te Mana Ora on (03) 364 1777:


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For further information, contact:

Karen Berry
Communications Manager
Te Whatu Ora South Canterbury  
021 139 7442