'Severe' bacterial bloom spotted near city’s most popular beach

LACONIA — A cyanobacteria bloom has polluted the water and killed fish in the Weirs Channel and is in danger of spreading to nearby, popular Weirs Beach, the state Department of Environmental Services said Friday.

Weirs Beach remained open for the time being.

Some cyanobacteria produce toxins that cause irritation of skin and mucous membranes, tingling, numbness, nausea, vomiting, seizures and diarrhea, the DES said. Chronic effects include liver and central nervous system damage. Pets can also be harmed. 

“Based on visual evidence, the cyanobacteria bloom appears severe,” said Amanda McQuaid, head of the DES beach program. “Sightings have been reported, located in the Weirs Channel behind Channel Lane, between Paugus Bay and Lake Winnipesaukee (not far from Weirs Beach).

“As a result, the New Hampshire Department of Environmental Services has issued an advisory for cyanobacteria. It is advised to look out for accumulations in other areas of the lake or shorelines. Please continue to monitor your individual shoreline for changing conditions and avoid contact.”

A cyanobacteria outbreak is marked by surface scum, green streaks or blue-green flecks.

Cyanobacteria occurs naturally in water, but it can bloom when excess nutrients are present in the water.

McQuaid said she spoke to city staff at Weirs Beach.

“They said, ‘Oh, it’s not coming this way,’ she said.

“But I’m pretty certain that with boats coming through the channel it will spread.”

McQuaid said dead fish were observed, which occurs when the bacterial takes up oxygen and release toxins.

Laconia Parks and Recreation Director Kevin Dunleavy didn’t immediately return a call for comment.