Masterton District is starting to keep a watchful eye on the algae levels in Henley Lake, given its past predisposition to increased cyanobacteria in the summer.
Cyanobacteria is always present in natural waterways, but when elevated temperatures cause algae levels to spike, it can be toxic to humans and dogs.
When this has happened in past summers, the council has urged the public [and pets] to avoid any contact with the water.
A spokesperson for the council confirmed that algae monitoring at the lake has begun.
“Cyanobacteria is monitored between October and April at Henley Lake. This includes composite water samples and visual monitoring.”
The spokesperson said algae blooms occurred due to a mixture of conditions.
“We are unable to predict when this will occur and to what extent. But given we have seen blooms regularly over past summers, we expect that will continue this year.”
Cyanobacteria is also monitored by Greater Wellington Regional Council [GWRC] in the region’s rivers.
The GWRC website notes that algae blooms tend to happen in water bodies with low-moderate nitrogen and phosphorus levels.
It said that when ingested, a piece the size of a 50-cent coin could be enough to kill a dog.
The lake is also in the middle of the bird nesting season in the wetlands area next to the lake, which requires a leash restriction for dogs in the area until November 30.
The spokesperson said this was going well so far, with no significant incidents of dogs breaking leash probation.
“Henley Lake hosts a variety of aquatic birds, including ducks, swans, and coots,” the spokesperson said.
“Where staff have been in the area, we have noticed good on-lead behaviour from dog walkers. We encourage this to continue while the nesting season is here.”
