Elevated levels of the potentially toxic algae have now been found in the Waikaia River at Waikaia.

Environment Southland currently has toxic algae alerts in place at the Aparima River at Thornbury, the Waiau River upstream of Excelsior Creek, and Upukerora River near Te Anau where a family's dog died after suspected contact with the toxic algae.

ES senior scientist Katie Blakemore reminded river users to remain alert for algal growth or mats of algae floating in the water and avoid contact.

While algae occurs naturally in waterways some species can, given the right conditions including warm weather and low river flows, produce toxins and rapidly bloom to harmful levels.

Toxic algae is commonly identified in waterways as a dark green/brown slime on rocks, or dark brown/black mats at the water’s edge. 

It can be harmful to people and animals if swallowed, or through contact with skin.

People and animals (it can be deadly to dogs, in particular) should avoid contact with the river and be mindful of the potential health risks, until health warnings are removed. 

If you experience health symptoms after contact with contaminated water, visit a doctor immediately. If you are concerned that any animals have consumed toxic algae or contaminated water, they should be taken to a vet immediately.

ES regularly monitors toxic algae at a number of river and lake sites across Southland.

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