Kāpiti Coast District Council is advising dog-owners to keep an eye out for toxic algae in the district’s waterways as the temperature rises. That includes lagoons in parks and reserves as well as rivers and streams.

Greater Wellington Regional Council are advising there are now dangerous levels in Waipoua River in the Wairarapa and elevated levels in Te Awa Kairangi (Hutt River).

Environmental Standards Manager Jacquie Muir, says seasonal changes that occur around this time of year impact on algae levels and it’s likely that we’ll soon see toxic algae in some parts of Kāpiti.

“We’re noticing the water levels slowly dropping and temperatures rising so it is possible cyanobacteria, an algae which is toxic to humans and deadly for dogs, will appear. We’re increasing signage at recreational swimming sites and taking this opportunity to remind people to be aware of the risks,” says Ms Muir.

The Council will maintain its seasonal monitoring program of recreational swimming sites, in partnership with Greater Wellington Regional Council. This happens weekly during the summer months.

Test results from popular river, lagoon and beach locations are available on the Council’s website.

Check for toxic algae

Signage at popular swimming sites is increasing to remind people to check for signs of toxic algae.

Toxic algae (cyanobacteria) generally form brown or black mats that grow on rocks in the river bed. Mats that come loose from the river bed can wash up on the river bank or form floating ‘rafts’ in shallow areas. When exposed, the mats may dry out and turn a light brown or white colour and may also produce a strong musty odour. Cyanobacteria differ from harmless bright green algae, which often form long filaments.

It is important to keep an eye on babies and toddlers who may put objects in their mouths. Seek emergency medical attention immediately if anyone in your group swallows toxic algae.

Caution should also be taken when exercising dogs by rivers as they are strongly attracted to the musty smell of drying mats and will eat them where they can, which could be fatal. The algae is quickly dispersed and deactivated by salt water, so it’s safer to walk your dog at the beach instead of at rivers during the summer.

Given the rapid growth of toxic algae and its potential change in coverage between weekly monitoring points people are also urged to know what it looks like.

“If you suspect toxic algae might be present then keep your dogs out of the water and let us know,” says Ms Muir.

Greater Wellington Regional Council has more information about toxic algae at www.gw.govt.nz/toxic-algae

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