Environment Southland has detected toxic algae in the Upukerora River at Te Anau Milford Road, marking the second Fiordland waterway to be affected by this harmful bloom in recent days.

In 2023 a pet dog died from suspected toxic algae poisoning after play in the Upukerora River.

Algae are a natural part of water ecosystems and often thrive in stable, fine weather conditions.

While most algae are harmless, certain species can produce dangerous toxins and bloom rapidly.

Key Information:

• Identification: Toxic algae typically appear as dark green or brown slime on rocks or as dark brown or black mats at the water's edge.
• Precautions: Water users should remain vigilant and avoid contact with the algae.
• Monitoring Limitations: Environment Southland cannot monitor all waterways, so similar algae growth may be present in other rivers in the region.
• Health Risks: Toxic algae pose significant health risks to both people and animals if ingested or through skin contact.
• Safety Measures: Keep dogs on leads and children away from affected areas. Seek medical attention immediately if health symptoms occur after contact with contaminated water. Take animals to a vet if they have consumed toxic algae or contaminated water.

Toxic algae alerts are also in place for the Whitestone River downstream of Manapouri-Hillside Road and the Waiau River near the Excelsior Creek inflow.

River users are encouraged to familiarize themselves with the appearance of toxic algae and stay informed through the Environment Southland's website.