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Two dogs dead – as toxic algae spreads in all regional rivers

News from Greater Wellington Regional Council
The death of two dogs from ingesting toxic algae from the Waipoua River reinforces the importance of monitoring dogs and children at riversides especially during hot dry summers which present ideal conditions for the growth of the deadly algae.

Both, we believe, died after eating toxic algae, which accumulate at river margins and are irresistible to dogs.

“We are very sorry to hear of this awful tragedy and we feel for the owners,” says the council’s Senior Environmental Scientist Dr Mark Heath. “Once dogs sense the musty odour of toxic algae, they go straight for it.”

Dr Heath says Greater Wellington has been warning of the presence of toxic algae in the Waipoua River over the last month, using riverside signage, media, social media and website channels to get the message across that extra vigilance is necessary during current weather conditions.

“We cannot have signage at all points along rivers, so it is vital that dog owners both learn how to recognise toxic algae and take a minute to check the status of rivers before they venture out with their dogs.”

Toxic algae grows on submerged river stones, presenting with a shiny brown/dark green to violet coating. It can also become unstable and detach, floating to the surface forming small brown/black mats at the water’s edge.

Specific site warnings are current for:

• Otaki River, warning extends from State Highway 1 bridge to river mouth
• Waikanae River, warning extends from Main Rd (old SH1) to river mouth
• Hutt River, warnings for Melling and Siverstream sites
• Waingawa River, warning for south road site
• Ruamahanga River, warning for Morrisons bush site
• Waipoua River, warning extends from Paierau Road to confluence with the Ruamahanga

River conditions will be reassessed on Monday.

It is also potentially toxic for people. People should see a doctor or contact Healthline 0800 611116 if you they been in contact with toxic algae and develop the following symptoms: nausea, vomiting, numbness, tingling, muscle twitches, shaking, weakness. Get urgent medical attention for anyone with breathing difficulties, convulsions or loss of consciousness.

News from Greater Wellington Regional Council – January 29
Toxic algae is quickly intensifying throughout the region, with all monitored rivers reaching health alert levels and Wairarapa’s Waipoua River remaining hazardous for swimmers. Otaki, Waikanae, Hutt, Ruamahanga and Waingawa river monitoring sites have exceeded the 20 per cent alert threshold, and the Waipoua River is above the 50 per cent “no swimming” line. Detached mats, which are particularly hazardous for dogs, have been seen in all rivers.

It is highly likely the same conditions apply to many non-monitored rivers in other parts of the region, so it would be useful for people visiting rivers to know what toxic algae looks like so that it can be avoided.

“Our message is clear. People should stay out of the Waipoua River and remain vigilant in other rivers,” says Greater Wellington Senior Environmental Scientist Dr Mark Heath.

“Levels are expected to increase, with hot dry conditions forecast for much of the region throughout next week.

“This comes on top of a prolonged dry spell. With the exception of the Otaki River, it’s been 35 days since the last decent flush for most rivers and streams in the region, which has produced ideal conditions for the growth of toxic algae.”

Warnings are being placed on the rivers shown below, and a range of media is being used to inform the public of risk levels around rivers.

Specific site warnings are:
• Otaki River, warning extends from State Highway 1 bridge to river mouth
• Waikanae River, warning extends from Main Rd (old SH1) to river mouth
• Hutt River, warnings for Melling and Siverstream sites
• Waingawa River, warning for south road site
• Ruamahanga River, warning for Morrisons bush site
• Waipoua River, warning extends from Paierau Road to confluence with the Ruamahanga

Toxic algae grows on submerged river stones, presenting with a shiny brown/dark green to violet coating. It can also become unstable and detach, floating to the surface forming small brown/black mats at the water’s edge.

Given conditions quickly change, people should be remain vigilant around rivers and streams throughout the region. This is the prime season for toxic algae, so look out for algae covering rocks and for detached mats in the water and lining riverbanks. If in doubt, stay out of the water and keep a close eye on children and dogs,

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.

See your doctor or contact Healthline 0800 611116 if you have been in contact with toxic algae and develop the following symptoms: nausea, vomiting, numbness, tingling, muscle twitches, shaking, weakness. Get urgent medical attention for anyone with breathing difficulties, convulsions or loss of consciousness.

Before you swim, stay safe by finding out about toxic algae at http://www.gw.govt.nz/safeswim/.

For more information on where it is safe to swim, go to: https://www.lawa.org.nz/explore-data/swimming/

News from Hutt City Council – January 24
Hot weather and low rainfall have combined to increase the risk of toxic algae with parts of the Hutt River now over the limit for safe swimming. Toxic algae has been found at the Silverstream monitoring site.

It grows on submerged river stones, presenting with a shiny brown/dark green to violet coating. It can also become unstable and detach, floating to the surface forming small brown/black mats at the water’s edge.

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.

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. They should check information signs around popular swimming areas.

News from Wellington Regional Council
Toxic algae has been found at a number of sites throughout the region and people should pick their swimming and dog walking spots carefully to avoid the risk to health from contact with the algae.

Monitoring by the Regional Council has found that levels of toxic algae are likely to continue to rise in the face of warm weather forecast for parts of the region over the coming week.

Key places to avoid are: the Waipoua River, where there is an extensive bloom and detached mats of algae; and the Waikanae River, where the Jim Cook Park monitoring site shows some detached mats.

Warning signs remain in place at the Waipoua and Waikanae rivers and people are strongly advised to avoid the Waipoua River where toxic algae and detached mats are widespread.

Levels are also rising on the Hutt River and swimming should be avoided at Silverstream. People should exercise caution at other points along the river and look out for evidence of toxic algae.

Toxic algae grows on submerged river stones, presenting with a shiny brown/dark green to violet coating. It can also become unstable and detach, floating to the surface forming small brown/black mats at the water’s edge.

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.

If you have been swimming in a river or lake and you have any of the following symptoms: nausea, vomiting, numbness, tingling, muscle twitches, shaking, weakness, breathing difficulties and potentially convulsions and loss of consciousness see your doctor immediately.

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.

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3 comments:

  1. Traveller, 29. January 2020, 16:55

    Does the Regional Council accept responsibility for this enormous and alarming spread of toxic algae? (Every year…)

     
  2. Guy M, 30. January 2020, 5:54

    Is there anything that can be done to destroy the algae? So, for instance if the toxic mats break free – can it be burnt? What happens to it long term? Does it become less toxic over time or does it stay there, malignant? Anyone know?

     
  3. Concerned Wellingtonian, 1. February 2020, 12:22

    A pity that strong farming interests have held sway over weak Regional Councillors.