Lake warnings

We monitor more than 100 popular recreational sites in Canterbury during summer. Health warnings are placed at sites where an increased risk of cyanobacteria or faecal contamination is present. Advisory notes may be present but are not an official public health warning.

Cyanobacteria can occur in any waterway, at any time, so it is important that you know what it looks like. Find out more about cyanobacteria in waterways and how you can protect yourself and your animals.

Faecal contamination poses a risk to health, check out LAWA’s swim smart checklist, to know what to check before you swim.

Te Roto o Wairewa / Lake Forsyth

31 January 2023
 

Te Mana Ora | Community and Public Health has issued a health warning after potentially toxic blue-green algae (planktonic cyanobacteria) was found in Te Roto o Wairewa - Lake Forsyth.

People should avoid the lake and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.

Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water.

Find more information about Mahinga Kai on the CPH website.

Environment Canterbury continues to monitor the lake weekly.

Eastern Kaiapoi Lake

30 January 2023
 

A bloom of potentially toxic algae (planktonic cyanobacteria) has been observed in the Eastern Kaiapoi Lake.

People and dogs should avoid contact with the water while the bloom is present. Contact with the water may cause skin and eye irritation. Drinking or accidentally swallowing water may result in illness.

Exposure to cyanobacteria may 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 the lake water. Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately.

Pegasus Lake

2 November 2022
 

Te Mana Ora Community and Public Health, part of Te Whatu Ora National Public Health Service, has issued a health warning after potentially toxic blue-green algae (planktonic cyanobacteria) was found in Lake Pegasus.

People should avoid the lake. Animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.

Exposure may 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 the lake water,

No one should drink the water from the lake at any time, boiling the water does not remove the toxin.

Animals that show signs of illness after contact with the water, algal mats, or scums should be taken to a vet immediately.

Lake Pegasus continues to be monitored on a regular basis.

Mata Kopae/St Anne’s Lagoon

07 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 with water at this lake.

Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water. No one should drink the water from the lake at any time. Boiling the water does not remove the toxin.

Exposure to cyanobacteria toxin may 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 the lake water.

Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately.

Find more information about Mahinga Kai on the CPH website.

Environment Canterbury continues to monitor the lake on a quarterly basis.

Te Waihora/Lake Ellesmere

8 February 2022
 

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 Waihora/Lake Ellesmere.

People should avoid the lake and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted. Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water.

Environment Canterbury continues to monitor the lake on a regular basis.

Find more information about Mahinga Kai on the CPH website.

Lake Rotorua (near Kaikoura)

Last updated 8 March 2019
 

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 basis.