Skip to main content
Published: 2016-01-13 00:00:00

What’s thought to be a harmless, but potentially smelly, red seaweed is being monitored closely by Waikato Regional Council after it has shown up on the Coromandel Peninsula in recent weeks.

The seaweed is suspected to be a red alga known as Spyridia filamentosa or Hairy Basket Weed. It’s native to New Zealand but also occurs across much of the world. Testing will shortly confirm whether this is correct.

“While this is a completely natural event, masses of this non-toxic seaweed being washed up can cause an unpleasant odour so we’re keeping a close eye on what’s happening and testing to see exactly what type of seaweed it is,” said the council’s Coromandel zone manager Tonia Clarkson.

“Any smell is likely to get worse as the seaweed starts to break down. We’re hoping nature will deal with it but, because of the odour risks, it is important to monitor it and we’re keen to hear from people spotting large accumulations of it on their local beach.”

The Coromandel situation comes after significant amounts of red seaweed were washed up on Northland and other east coast beaches.

“Over summer it’s actually common for this type of seaweed to accumulate in large clumps. Those clumps are normally found offshore and further north of the Waikato region but the recent strong winds we’re experiencing courtesy of El Nino have bought them our way,” said Ms Clarkson.

“Something similar happened last year on the Coromandel when we had close to El Nino weather but the red seaweed washing up was confined to Whangapoua. Now we’ve had reports of it at New Chums, Rings Beach, Matarangi and Cooks Beach.

“We’ve got staff out checking where else it might be and we’re keen to hear from anybody who’s spotted it at their local beach.”

People wanting to report sightings can call the council’s freephone 0800 800 401.