Red alert warnings are active across four waterways in the greater Wellington region: the Hutt River at Silverstream, the Waipoua River at Colombo Road, and the Ruamahanga River at both Double Bridges and Te Ore Ore.
Greater Wellington Regional Council is urging the public to avoid all four sites and to keep dogs well clear of the water. The hazard is toxic algae, a neurotoxin that acts like snake venom, making it extremely dangerous to people and lethal for dogs if ingested.
Penny Fairbrother, Greater Wellington's senior advisor integration and insights, explained how the risk develops and why it so often catches people off guard. "Toxic algae lives on the riverbed, where it's usually out of reach," she said. "But during a flare-up like this, thanks to warm weather and a lack of rain, the algae lifts off the rocks and accumulates at the river's edge, where it poses the biggest risk, especially to dogs who seem to love the smell and will try to eat it if given the chance."
"Even a small amount of toxic algae, the size of a 50-cent piece, can be enough to kill a dog," Fairbrother said.
Greater Wellington conducts weekly monitoring of popular swimming spots across the region. Before visiting any Wellington river, people are encouraged to check the LAWA website for the latest toxic algae warnings and alerts.
Anyone feeling unwell after contact with algae should see a doctor or call Healthline on 0800 611 116. If a dog is suspected of having swallowed toxic algae, owners should get to the nearest vet immediately.
