Henley Lake algae a risk to pets

STAY OUT: Signs at Henley Lake warn people away from water activities.

Toxic algae, the scourge of waterways in summer, has again been detected in Masterton's Henley Lake, prompting a warning to dog owners from the Masterton District Council.

Dogs are not to be let off their leads around the lake until such time as the council advises it is safe to do so.

The warning follows the discovery of toxins related to the decay of algal bloom, says the council's parks and facilities manager Grant Hathaway.

"A health warning was issued earlier this week and signs have been put up at the lake after localised algae blooms were identified. This is a cautionary approach taken by council to ensure that lake users are not exposed to these toxins.

"Exposure to cyanobacteria, or toxic algae, may cause symptoms such as skin rashes, nausea, tummy upset and tingling and numbness around the mouth or tips of fingers.

"If you or your pets experience health symptoms after contact with contaminated water, contact your doctor or vet immediately," Mr Hathaway said.

He described the toxin as causing "a thick surface scum" covering localised areas of the lake shoreline.

Also noticed was a light blue/white streak of decaying cells that are releasing pigments. This was a common occurrence during bloom decline, he said.

"Cyanobacteria occur naturally but can increase rapidly during summer months. If the water is cloudy, discoloured or has small globules suspended in it, avoid all contact.

"Not all cyanobacterial blooms are visible to the naked eye and toxins can persist after the bloom has disappeared.

"Cyanobacterial concentrations can change quickly with changing environmental conditions, like wind. If a health warning is in place, avoid contact with the water."

Mr Hathaway said the council would continue to monitor the lake and people would be advised of any significant changes in water quality that could affect public health.

Toxic algae has been found in Henley Lake over many years in the past, including last summer when it was also discovered in the Waipoua River at Colombo Rd and the Ruamahanga River at Kokotau.