River users need to be aware of toxic algae in Southland waterways this summer, a senior water quality scientist says.
Environment Southland (ES) senior surface water quality scientist Katie Blakemore said while most algae were harmless, some were not.
"The toxins found in these algae are dangerous to humans and animals and it is not safe to swim if [toxins] are present in a waterway."
Cyanobacteria, also known as toxic algae, was widespread in many New Zealand water bodies — including clean water. It could also establish itself in still water like bird baths, fountains and ponds.
Blooms were more likely to occur during summer when rivers were low.
"We encourage river users to take the time to know what to look for and to keep informed.
"Look for dark green/brown slime on rocks or dark brown/black mats at the water’s edge," she said.
The Waiau River downstream of the Excelsior Creek junction, and Hamilton Burn at Affleck Rd, both affected by algae blooms in the past, have current alerts in place.
ES monitors seven sites weekly for the algae during the summer, and 30 sites monthly throughout the year.
Ms Blakemore said many locations were not regularly monitored, or toxic algae blooms might have formed since a location was last monitored.
"We would advise that when you visit any river, check for toxic algae before entering the water.
"If you see toxic algae — stay out of the water and keep your dog on a lead.
"If a person or animal comes in contact with toxic algae and becomes unwell, seek medical or veterinary advice immediately," she said.
- By Toni McDonald
