The reservoir at Irishtown Nature Park in Moncton has been shut down for recreational use.

Blue-green algae was found in the reservoir during routine testing, city officials said Monday.

“Kayaking, canoeing, and other recreational activities are prohibited, and pet owners are asked to keep their dogs out of the water and not let them drink or swim in the water,” the city said in a news release.

Notices and signage have been posted, and the city said it will continue to monitor the situation.

Cyanobacteria, also known as blue-green algae, are naturally occurring bacteria found in many New Brunswick ponds, lakes, and rivers.

Officials said the bacteria are not normally visible, but under certain conditions, can increase in numbers to form surface blooms.

While not all cyanobacteria are harmful, some can produce toxins that can impact the nervous system, liver, and skin.