Look out for toxic algae in rivers and streams


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Look out for toxic algae in rivers and streams

  • Date 2:40 PM Tuesday 18 February 2020
  • Type Rivers, Rainfall & Reserves

Toxic algae is starting to show up in some of Marlborough’s streams and rivers. Parents and dog owners are warned that it poses a health risk to children and animals. The algae is present in parts of the Taylor, Omaka and Wairau rivers.

Council has placed warning signs at some of the river access points but it’s important people are aware of the algae and that it could be present in other areas too.

If the river bed is covered in thick brown or black mats that have a velvety texture and an earthy or musty smell, it is wise to be cautious and avoid that area. Algal mats can also float at the river's edge or in shallow water, or attach to rocks in fast-flowing parts of a river.

The toxins in the algae have the greatest effect on dogs, which are attracted to the smell and can die after eating it. While there have been no reports of dog deaths from algae in Marlborough, there have been cases in the Nelson-Tasman region. If you think your dog has eaten toxic algae take it to a vet immediately.

In humans, contact with toxic algae causes vomiting, diarrhoea and skin irritation. It is therefore important to keep children away and avoid touching it or swimming near it.

You can find out more about toxic algae, including information on how to identify it, on this website:

Go to Toxic Algae section


The information in this media statement was correct at time of publication. Changes in circumstances after the time of publication may impact on the accuracy of the information.