As ocean becomes more acidic, will ‘dead mud’ consume Maine’s bountiful shellfish flats?

AUGUSTA, Maine — The spread of “dead mud” among Maine’s shellfish flats could have disastrous implications for clammers, lobstermen, oyster farmers and others whose livelihoods depend on healthy coastal ecosystems.

What’s the source of this new threat to one of the state’s most important natural resource industries? Several indicators point to the acidity of the ocean as the culprit.

All along the coast, environmental groups and marine biologists are seeing a correlation between higher acidity levels in seawater, lower landings of shellfish and reproductive problems at aquaculture facilities, but there is little data to prove it. A bill sponsored by Rep. Mick Devin, D-Newcastle, who works as a marine biologist, seeks to solve the mystery.

LD 1602, which would establish a panel of experts to study the problem, has the support of the state’s Department of Marine Resources and would cost $25,000 or less, according to Devin.

“Maine’s marine resources support a $1 billion industry and thousands of jobs,” said Devin, who introduced the bill to the Legislature’s Marine Resources Committee on Monday. “Ocean acidification has the potential to shut down Maine’s shellfish industry and we can’t afford to lose it.”

Patrick Keliher, commissioner of the Department of Marine Resources, testified Monday in support of the bill, which is being sponsored as an emergency measure, meaning the study commission would be formed immediately after enactment.

“Every day we hear from fishermen that the conditions they have seen on the water have been changing rapidly and dramatically in recent years,” said Keliher. “Water temperatures are warmer, sheds are less predictable, new species are present and others are disappearing. Acidification is one of many stressors in our marine environment, and there is much we do not know about the sensitivity of important commercial and recreational fisheries to reduced pH.”

The pH scale is used to measure acidity. According to testimony from the Rockland-based Island Institute, the pH in the Gulf of Maine stood at about 8.2 for 600,000 years but has dropped to 8.1 in the past two centuries.

That might not seem like much, said Susie Arnold, a marine scientist for the institute, but because acidity is measured on a logarithmic scale, 8.1 is 30 times more acidic than 8.2. The Gulf of Maine is especially susceptible to acidification because of water temperatures and an above-average influx of fresh water.

The rise in acidity is thought to be due to carbon dioxide, which finds its way to the oceans after being produced by the burning of fossil fuels, either through the air or stormwater runoff. Acidification has already been linked to precipitous drops in populations of organisms with shells and exoskeletons on the West Coast and now there is growing concern that the trend will decimate shellfish, lobsters and micro-organisms here on the Maine coast.

“Right now, we’re really looking to understand what we don’t know,” said Nick Battista of the Island Institute, which will host an ocean acidification forum beginning at 9 a.m. on Thursday at the Governor Hill Mansion in Augusta.

Joe Payne of Westbrook, Casco baykeeper for Friends of Casco Bay, said small-scale observations show higher acidity in some areas of Casco Bay where shellfish harvesters aren’t finding their bounty.

“We have anecdotal information from the harvesters themselves,” said Payne. “They say there’s more and more dead mud. There’s mud they can’t harvest from, and Casco Bay is not unique to the coast of Maine. There are more and more areas where they can’t harvest a day’s pay worth of clams.”

The lobstermen are also concerned, according to David Cousins, president of the Maine Lobstermen’s Association.

“The more I hear about it, the more I have concerns,” said Cousins. “We don’t really know the effects of ocean acidification on lobsters, but we do know the effects on shellfish and clams and it’s not positive. As long as the industrial nations of the world use fossil fuel, it’s going to get worse.”

Bill Mook, who has owned Mook Sea Farm, an oyster seed hatchery in Damariscotta, since 1985, said he also has noticed that when the water acidity is higher, such as after a storm, his oyster seeds suffer.

No one spoke against the bill during a public hearing on Monday, but if the study moves forward the question becomes what to do with the results if they say that disastrous acidification has arrived. Ivy Frignoca, an attorney for the Conservation Law Foundation, said that despite being nearly powerless in some ways — such as stemming carbon dioxide emissions in upwind states — Maine can take steps against ocean acidification.

“The carbon, as we understand it, is coming from all fossil fuel emissions and there’s not a whole lot we can do about that because some of it is coming from outside the region,” she said. “The second source is from stormwater runoff and that is something we can do something about.”

Christopher Cousins, Bangor Daily News, 13 January 2014. Article.

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