Care urged for swimmers and dog walkers as toxic algae blooms in Waipoua River

A severe toxic algal bloom has developed along the whole of the Waipoua River in Wairarapa, with algae and detached mats building up at the river margins. People and their pets are urged to avoid the river and its banks until conditions improve.

Eighty percent of the riverbed is covered with the algae and there is a constant stream of floating/detached mats.

"This is as bad as it gets and represents a very real risk to human and animal health. People are warned to stay away from the river," says Greater Wellington senior environmental scientist Dr Mark Heath.

Toxic algae grows on submerged river stones in a shiny brown/dark green to violet coating. It can also become unstable and detach, floating to the surface forming small brown/black mats at the water's edge.

Wherever toxic algae is present it is important to keep an eye on babies and toddlers who may put objects in their mouths. Seek emergency medical attention immediately if anyone in your group swallows toxic algae. Dogs, in particular, are attracted to the aroma of toxic algae, which can be fatal for them if eaten.

If yourself or others have been swimming in a river or lake and have any of the following symptoms: nausea, vomiting, numbness, tingling, muscle twitches, shaking, or weakness, see your doctor.  Seek immediate medical attention for more serious symptoms such as breathing difficulties, convulsions or loss of consciousness.

Before you swim, keep yourself safe by finding out about toxic algae.