Toxic algae blooms in the Ruamahanga and Kapiti Coast catchments - check before you swim and keep dogs on leashes

  • Published Date 12 Feb 2021

Greater Wellington is urging the community to check for LAWA website warnings and alerts, following the emergence of toxic algal blooms in several rivers in both the Ruamahanga and Kapiti Coast catchments.

Greater Wellington advises caution to swimmers in the Ruamahanga and Kapiti Coast catchments and to keep dogs on leashes - as new amber alert level warnings are in place for Otaki River and the whole of the Ruamahanga River.

Greater Wellington senior environmental scientist, Dr Mark Heath says, "Toxic algae has increased to amber alert levels in the Ruamahanga and Otaki rivers so we strongly advise to check for toxic algae before you swim, and to keep all dogs and children away from the river's edge. With warm and dry weather predicted over the next week it is likely that this risk will increase.”

"These warnings are in addition to amber alert warnings that are already in place along the Waikanae River in Kapiti, as well as Waipoua River and Waingawa River in the Ruamahanga catchment.  

"It's important we all scrub up on the facts so we can all keep safe this summer, as toxic algae can be harmful to people and dogs.

"Algal mats grow on the rocks in the riverbed and form leathery dark green or black mats, which can break off and accumulate at river edges. As the algal mats dry out they can become light brown colour, and have a distinctive deep earthy or musty smell," says Dr Heath.

Dogs are mostly at risk because they like the smell and taste of toxic algae. Even a small amount - about the size of a 50 cent piece, can be enough to kill a dog.

Owners especially need to be vigilant of their dogs sniffing out toxic algal mats which can wash up at river edges.

Greater Wellington is currently monitoring these popular swimming spots on a weekly basis to make sure the community knows when it's safe to swim. To check if an area is suitable for swimming see the LAWA website.

It's important the community keeps informed by checking LAWA alerts and following warning signs, so we can all look after our whānau and beloved pets this summer.

If you have been in contact with toxic algae and are feeling unwell see your doctor or ring Healthline 0800 611 116. Seek urgent medical attention for anyone with breathing difficulties or convulsions. If you think your dog has swallowed toxic algae, take it to the nearest vet immediately.

Learn more out toxic algae.

Check for toxic algae alerts at the LAWA website.

Updated March 30, 2022 at 3:11 PM

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