Warning to watch for toxic algal mats in rivers and streams

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Warning to watch for toxic algal mats in rivers and streams

Areas of toxic algae are starting to show up in some of Marlborough’s streams and parents and dog owners are being warned that it may pose a health risk to children and animals.

Council staff have spotted high concentrations of the algae in parts of the Omaka River and the Wairau River. While Council has placed warning signs at some of the access points it is important people are aware of the algae and that it could be present in other areas not just those signposted.

Not all river sites are monitored so if the bed of a river 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 river site.

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

In humans, contact with toxic algae can cause vomiting, diarrhoea and skin irritation. It is therefore important to keep children and dogs away from the algae; avoid touching it or swimming near it.

Algal mats may be floating at the river's edge or in shallow water or attached to rocks in fast-flowing parts of a river.

Find out more about how to recognise toxic algae


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.