Lakes - planktonic cyanobacteria warnings

Planktonic cyanobacteria are floating algae suspended in slow moving water such as in a lake. It often produces bright green or blue-green soup-like scums.

Routine monitoring for potentially toxic planktonic cyanobacteria is carried out monthly for Te Roto o Wairewa/Lake Forsyth and Te Waihora/Lake Ellesmere. This increases in frequency when potentially toxic planktonic cyanobacteria are identified.

East and West Kaiapoi Lake and Halswell Quarry Ponds

1 April 2019

Surface scums of potentially toxic blue-green algae (planktonic cyanobacteria) were observed in the East and West Kaiapoi Lakes and the Halswell Quarry Conservation Ponds.

People and animals, particularly dogs, should avoid contact with the water if there are visible surface scums present, or the water is cloudy, discoloured, or has small globules suspended in it.

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.

Te Waihora/Lake Ellesmere

24 December, 2017 - last updated 8 March 2019

The Community and Public Health division of Canterbury District Health Board has issued a health warning after high concentrations of blue-green algae (planktonic cyanobacteria) were found in Te Waihora/Lake Ellesmere.

People and animals, particularly children and dogs, should avoid contact with the water until the health warning has been lifted.

Environment Canterbury monitors the lake fortnightly and the public will be advised of any changes that are of public health significance.