BRUNSWICK

The Maine Department of Marine Resources continues to monitor a Casco Bay algae bloom that’s sucked the oxygen out of a 14- acre swath of Maquoit Bay, killing shellfish.

In Brunswick, the bloom may impact 100,000 pounds of clams, resulting in a loss of a quarter of a million dollars in wholesale profit.

Brunswick Marine Warden Dan Devereaux said Monday since he was first alerted to the die-off by clammers, the bloom has not spread. About 80 percent of the clam beds in the identified area have died, and Devereux said the innards of the mollusks are rising to the surface. He said the town planning department will continue to survey the situation in conjunction with the Department of Marine Resources and Department of Environmental Protection.

Only soft-shell clams have been impacted by the growth, he confirmed, adding this bloom is atypical to the area, making the mud oxygen-deficient only in that concentrated location.

Maquoit Bay connects to the much larger Casco Bay, where the phytoplankton bloom is affecting areas from Cape Elizabeth to the New Meadows River. A Marine Resources press release notes that phytoplankton counts “have significantly declined in most areas” being monitored.

“Observations by DMR staff and reported from the public indicate discoloration of the water and smells have decreased or dissipated completely,” the release notes. “Dissolved oxygen levels in the water are variable with the lowest levels measured in Maquoit Bay … and the New Meadows. … Other areas sampled for dissolved oxygen from Portland to Harpswell have normal levels. Field observations from Maquoit Bay in Brunswick indicate large patches of dead soft-shelled clams likely due to recent anoxic events.”

The state said samples of softshell clams, hard clams and mussels are still being collected. This particular bloom, Karenia mikimotoi, is not a threat to public health, the state said, but is harmful to marine life and has been linked to fish kills in Australia, Ireland, Korea and Alaska.

Devereaux said Monday there are several factors that caused the bloom, including the spell of hot weather and nitrogen run-off.

The department has reached out to the shellfish industry, aquaculture lease holders and seafood dealers in Casco Bay region, informing them of the bloom and advising them to develop plans to protect their product if effects of toxins or low oxygen are identified.

Devereaux said area shell fisherman have been in constant communication with him, each other, and the Department of Marine Resources regarding where the bloom may be headed and whether the bloom is spreading.

“It’s part of life in Maine, and we have to be diligent about identifying areas and developing strategies to minimize impact,” he said.

About 50 clammers are impacted by this bloom. Others clammers could be impacted in the future, as the town decides how many licenses to issue each year based on the previous year’s landings.

“The economic trickle down can be a big impact to a community,” Devereaux said.