Toxic cyanobacteria can occur at a number of popular freshwater recreation sites throughout Canterbury. It can kill animals and it is a danger for young children. Routine monitoring for the presence of potentially toxic cyanobacteria is carried out at a number of popular recreation sites throughout Canterbury during summer.

Know what to look for when visiting rivers or lakes

Cyanobacteria (blue-green algae) can make humans and animals extremely sick. Dogs are particularly at risk if they swallow the algae or algal mats when swimming and drinking from rivers and lakes. View the toxic algae video below to know what to look for.

Not sure? Don't risk it

Warnings will not be in place at all spots where animals could enter the water. It is important to know how to identify cyanobacteria mats and prevent your animals from coming into contact with them.

For more information about cyanobacteria, and river and lake warnings, call us on 0800 324 636 or view the warnings below.

Rivers - benthic cyanobacteria warnings

View the latest cyanobacteria river warnings.

Find out what you need to know

  • Cyanobacteria occur naturally all year round, but are more common during the warmer months
  • Not all cyanobacterial blooms are visible, and toxins can remain after visible blooms disappear
  • Cyanobacteria concentrations can change quickly, such as on windy days
  • Symptoms of cyanotoxin poisoning in dogs include panting, lethargy, muscle tremors, twitching and convulsions. These symptoms usually occur within 30 minutes, and can be fatal.
  • We monitor popular freshwater recreation sites in Canterbury during summer, and places health warnings (link to warnings page) at affected spots.  However, cyanobacteria can occur at any time, and warnings can’t be placed at every freshwater spot at risk of cyanobacteria.  View the toxic algae video to know what to look for.