Monday, 21 December 2020, 3:11 pm
The Otago Regional Council (ORC) is asking dog owners to
learn how to recognise potentially toxic algal mats in
rivers, in order to keep their pets safe this
summer.
Phormidium, a naturally occurring algae,
thrives in Otago rivers during summer – particularly the
Cardrona, Hawea and Manuherekia Rivers, but it has also been
spotted in other parts of the region, such as the
Waianakarua River and Silver Stream.
Phormidium forms
thick dark brown mats on rocks in the riverbed and can
sometimes look like black tar. In the flow of water,
phormidium mats detach from the riverbed and wash up on