Algal Bloom Detected at Pegasus Lake

Published: 14-May-2019

Updated March 2019: The health warning mentioned in this article for Pegasus Lake has been lifted and the water is currently safe for swimming.

Lake Pegasus was previously off-limits for swimming, after the Canterbury District Health Board  identified potentially toxic blue-green algae (planktonic cyanobacteria) in the water and issued a public health notice.

Warning signs were put in place around the lake notifying passers-by of the health danger posed by the water.

While the lake has been impacted on by algal bloom in the past, it had enjoyed a clean bill of health this summer, up until this warning notice.  People and animals, particularly children and dogs, should avoid contact with Lake Pegasus until the warning has been lifted.

The bloom will be monitored on a weekly basis and the public will be advised of any changes to its status.

Facts about cyanobacteria:

  • The algae occur naturally but can increase rapidly during warmer months.
  • If the water is cloudy, discoloured, or has small globules suspended in it, avoid all contact.
  • Not all cyanobacterial blooms are visible to the naked eye and toxins can persist after the blooms disappear.
  • Cyanobacterial concentrations can change quickly with changing environmental conditions (e.g. wind). If a health warning is in place avoid contact with the water

Learn more:

Toxic Algae Information Brochure

Toxic Algae FAQs