Algae | New Hampshire Public Radio

Algae

A lake with a bright green slick across it, demonstrating the presence of cyanobacteria in the water.
Wikimedia Commons

New Hampshire's lakes are seeing more toxic algae blooms than normal this early in the season, according to state officials. 

Over a dozen cyanobacteria blooms were reported in the week after Memorial Day, the N.H. Department of Environmental Services says. There are normally just a few reports during this time of year.

Chris Nash, NH DES

Nearly two months after implementing a ban on shellfish harvesting in coastal Atlantic waters, environmental regulators say a potentially toxic algal bloom has subsided to safe levels.

In early June, regulators found extremely high levels of a marine algae capable of producing a neurotoxin that can build up in shellfish.

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Chris Nash / NHDES

The state is temporarily banning shellfish harvesting in coastal Atlantic waters because of a severe bloom of potentially toxic algae.

The ban applies to mussels, clams and oysters in near-shore and offshore waters. It does not apply to lobsters, or to inland areas, such as Great Bay and Little Bay.

The advisory also does not indicate a threat to swimmer or surfers, who were allowed back onto the Seacoast beaches as of Monday.

Texas A&M AgriLife

The Department of Environmental Services has been issuing more warnings than it usually does at this point in the summer for algal blooms, potentially toxic mats of cyanobacteria.

But David Neils, chief water pollution biologist at the department, says that uptick is partly caused by an increase in public awareness.

“People are becoming educated about cyanobacteria, so they’re looking for them more often, and call us more often.”

Some of those blooms that residents call DES about are small or nontoxic, but the department issues a warning just to be safe. 

USGS website

Cyanobacteria advisories are in place at Elm Brook Park beach in Hopkinton and Silver Lake State Park Beach in Hollis. 

State officials are urging visitors to stay out of the water if they observe blue-green scum or clumps suspended in the water column. Cyanobacteria can be toxic to both humans and dogs.