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September’s algae bloom has faded from the waters around Harpswell, but harvesters and growers are still taking stock of the damage.
Some of the most vulnerable species, like worms and soft-shell clams, appear to have been wiped out in certain areas, while hard clams and oysters mostly survived. But with the bloom happening just before winter, growers and harvesters say they will have to wait for spring to know if the stress and lack of nutrients will lead to more losses.
Clam diggers and others started seeing signs of the bloom around Sept. 8 and 9. Dead and dying shellfish and worms were found on mudflats at the head of Middle Bay, in Long Cove, and in other areas, while some places in Harpswell saw no impacts at all. Maine’s Department of Marine Resources and other authorities soon confirmed that the bloom was spreading from Casco Bay as far south as New Hampshire and Massachusetts.
Tests revealed that the bloom contained the plankton Karenia mikimotoi, which is toxic to shellfish but not dangerous to humans. In addition to the plankton’s toxicity, any large algae bloom uses up oxygen, suffocating marine life. Those decomposing animals further deplete oxygen, both in the water and the mud, and can increase acidity.
The near-shore bloom seemed to peak around the middle of September. There were fears that a large storm that moved up the East Coast in the last week of September might push offshore algae back into Maine’s bays, but the storm ultimately tracked away from land and had minimal impact on Harpswell.
On Oct. 9, Harpswell Harbormaster Darcie Couture reported on Facebook that there were no more visible signs of the bloom, even offshore.
Harpswell clam digger David Wilson, who chairs the town’s Marine Resources Committee, said that in Long Cove and Middle Bay, he and other harvesters have found that larger quahogs, also known as hard clams, survived the event, while younger clams and seed clams did not. Wilson said it could take as many as seven years for populations to rebuild. And he worries that even the clams that did survive the bloom might not make it through the winter if they haven’t built up their fat stores sufficiently.
Bloom’s impact extends to sea farms
Harpswell has more than 100 aquaculture leases, with oysters as the main crop, and farmers reported mixed experiences of the bloom.
Kat Lipp, general manager of Mere Point Oyster Company, on Middle Bay in Brunswick, estimated that the farm lost about 20% of its oysters from the bloom. The farm discovered the harm early on, before the bloom was fully evident. When the extent of the threat became clear, Lipp said, staff stopped handling the oysters to reduce stress on them and give them the best chance of survival.
Like Wilson, she said it remains to be seen how many of the oysters will survive the winter.
Snow Island Oysters, which farms oysters on Harpswell Sound near the north end of Orr’s Island, has not seen an unusual die-off, according to Tait Nygaard, farm manager. The farm has been cautious about handling oysters, he said. He speculated that its location closer to the open ocean may have been a safer spot than farther up in the bays.
Another oyster farmer, Seth White, said his shellfish near Little Birch Island in Middle Bay seem to be doing OK. But his other crop, urchins, was hit hard. White said that when he pulled them up in the middle of September, he found many dead urchins. Some of the live ones didn’t look so good either.
White said he only knows of one other urchin farm, in Portland, and he heard that it survived the bloom. He said it may be a few years before he can try to grow urchins again, because their seed can cost 40 times as much as oyster seed.
He got his urchin seed from the University of Maine through a grant. This was his first time trying to grow them, and he had hoped they would be ready to sell next season. Now he’ll have to wait years to see if urchins can be an economically viable crop.
A more immediate concern for many in the aquaculture and harvesting industries is the immediate loss of income. White said that when oyster farms decided to take a break from their usual schedule of harvesting and handling oysters to give the shellfish a better chance of surviving the bloom, farm workers saw their hours cut. He knew of a dozen or more people at the end of September who hadn’t had any work to do.
At Mere Point Oyster Company, Lipp had a similar message. “The folks out there really being affected by this are the diggers, the farmers, the wild harvesters — the individuals, not the companies,” she said. It will likely be months more before the full effects on workers is known.
