Christchurch dog owners warned as toxic algae found in popular waterways

City Council staff have warned dog owners in Christchurch to be aware that potentially toxic algae has been found in several popular public spaces. Photo / Andriyko Podilnyk, Unsplash

City Council staff have warned dog owners in Christchurch to be alert as potentially toxic algae has been found in several popular public areas.

At least four parks have seen waterways test positive for cyanobacteria, a toxin that can cause lethargy, muscle tremors, convulsions and paralysis in animals that consume it.

The algae found in rivers will present itself as dark brown or black mats, which have a slimy or velvety texture and musty smell.

Cyanobacteria can turn lakes green but in rivers it usually occurs as dark brown mats attached to rocks or on the surface in shallow, slow-flowing water.

The smell, unfortunately, can be attractive to dogs, according to Principal Waterways ecologist Dr Belinda Margetts.

“It is something people should be aware of if they are walking their dogs by rivers, streams, ponds and lakes or engaging in activities, such as kayaking, where they might come into contact with algae in the water,” she said.

The algae can be fatal to dogs. At this stage, it’s been found in Hewlings Stream at Jellie Park in Burnside, Yaldhurst Bush, Arthur Adcock Memorial Reserve and Springlands Reserve.

Te Mana Ora (Community and Public Health) has issued public health warnings for potentially toxic algae at Pegasus Lake and Lake Forsyth.

“[During summer] it is likely that we’ll find more toxic algae, so people need to keep an eye out and avoid contact with any water that may have potentially toxic algae in it.”

If a dog owner believes their dog may have consumed cyanobacteria, Council’s advice is to contact their local vet immediately.

Humans who have been in contact with water that contains cyanobacteria might experience tingling or numbness around the fingertips or mouth.

They might also have breathing difficulty, gastrointestinal symptoms, or skin rashes.

People who feel any of these symptoms after contact with a waterbody should seek medical advice from their doctor or call Healthline.