Toxic algae in Waipoua River - a reminder to check before you swim

  • Published Date 06 Nov 2020

Greater Wellington Regional Council is urging the community to check for warnings and alerts, following the emergence of a toxic algal bloom in the Waipoua River.

Toxic algae is a reoccurring issue for our region's fresh waterways when water temperatures warm and water levels lower.

Already with problematic levels of toxic algae detected in Waipoua River, alerts have been issued to inform the community if it's safe to swim and let dogs off leashes.

Greater Wellington senior environmental scientist, Dr Mark Heath says, "We've detected the toxic algae above guideline levels in the Waipoua River, fortunately, there are no detached mats washing up at the river's edge so at this stage the risk is not extreme. However, we advise against swimming and letting your dog of it leash. It is very likely as the weather gets warmer that this risk will increase."

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

"Algal mats grow on the rocks in the riverbed and form leathery dark green or black mats, these mats can become unstable and slough of the rocks and accumulate river edges at the as they dry out they can become light brown colour, and are distinctive for their 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.

"Toxic algae isn't the only harmful thing lurking in our water this summer, bacteria such as E.coli in fresh water and Enterococci in marine water can cause serious harm to people.

Greater Wellington monitors popular swimming spots on a weekly and fortnightly basis to make sure the community knows when it's safe to swim.

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

"In general, a good rule of thumb is to stay out of fresh or sea water for 48 hours after rain, and always check for warning signs," adds Dr Heath.

If you think you have swallowed toxic algae, seek medical attention immediately by calling 111, or 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.

Updated March 30, 2022 at 4:58 PM

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