26 Feb 2024

Keep your eyes peeled for potentially toxic algae in Christchurch waterways.

Every summer the toxic algae cyanobacteria appears in our waterways, and the recent bout of hot and dry weather has made it more prevalent than usual.

Christchurch City Council Head of Three Waters Brent Smith says the potentially toxic algae has been confirmed in at least one pond and could be present in others.

“Animals can get very sick if they ingest the algae, and dogs are naturally drawn to investigating its musty smell. If dogs lick or ingest the material it can be quick acting and fatal.” 

“Potentially toxic algae has recently been seen in Wigram Pond, but it’s important to remember that it can be present in any freshwater waterbody so learn what to look out for, and if in doubt keep your dog away from the water,” Mr Smith says.

The algae typically presents in rivers as dark brown or black mats, with a slimy or velvety texture and a musty smell.  The algae can make water look cloudy, discoloured, or like it has small globules in it.

Learn more about cyanobacteria.

Te Mana Ora (Community and Public Health) has issued public health warnings for potentially toxic algae at a number of places in Canterbury.

Cyanobacteria poisoning symptoms

Symptoms of cyanobacteria toxin poisoning in animals include lethargy, muscle tremors, fast breathing, twitching, paralysis, and convulsions. If you suspect your dog is suffering from cyanobacteria poisoning, contact your vet immediately. 

For humans, if you have been in contact with water containing cyanobacteria, you may experience tingling or numbness around the fingertips and/or mouth, breathing difficulty, gastrointestinal symptoms, or skin rashes. If you feel any of these symptoms after contact with a waterbody, seek medical advice from your doctor or contact Healthline on 0800 611 116.