Carter Newell owns and operates one of the most productive mussel farms in the state of Maine. One frigid spring morning I joined him and his two-person crew on a short boat ride to the barge he calls Mumbles, a 60-by-24-foot vessel anchored that day in a quiet cove in the brackish Damariscotta River. Named for the Welsh seaside town where Newell once did research, Mumbles was tethered to a steel-framed raft hung with hundreds of 45-foot ropes, each thick with thousands of mussels in various stages of development.
I shivered in the piercing wind as a crew member stepped from Mumbles onto the shifting raft to identify mussel ropes ready for harvest. Newell remained on the barge to helm a 16-foot crane that hauled up the designated ropes, each heavy with a Christmas tree–shaped aggregation of roughly 3,000 mussels. An outsized brush then swept the bivalves off the ropes and into an enormous stainless steel bucket. Another machine funneled them into a heavy polyethylene bag the size of a baby elephant, from which they were poured onto a conveyor-belt apparatus to be scrubbed, sorted and bagged. Newell designed this ungainly Willy Wonka–esque apparatus over decades in a costly process of trial and error that faced—and ultimately overcame—several challenges, including protecting the mussels from turbulent seas and voracious eider ducks.
As he oversaw the morning harvest, Newell, who has a Ph.D. in marine biology, talked some science—the dynamics of phytoplankton, why nitrate chemical concentrations increase in the winter, how chlorophyll levels for the entire coast of Maine can be mapped with just three satellite images. Mostly, though, he talked about mussels: their life cycle, their geographic distribution, how to prepare them (don’t spare the garlic) and—critically—how best to farm them without going broke. “Fish farming is no way to make a quick buck,” he told me.
The truth is that soon fish farming may be the only way for Maine’s struggling seafood workers to make any bucks at all. Thanks to overfishing, parasites and rising ocean temperatures, among other threats, nearly all of Maine’s commercial fisheries are in free fall. Maine cod is crashing, as are local shrimp. The wild mussel catch declined from 25 million pounds to a mere nine million over the past two decades. And lobsters, by far the state’s most profitable catch, are scuttling north to cooler Canadian waters. None of this bodes well for the state’s once robust seafaring economy: the average age of a Maine commercial fisher hovers above 50, suggesting that many young people have lost faith in the work.
Mussel harvesting at Pemaquid Mussel Farms in Bar Harbor, Maine, is overseen by farm owner and marine biologist Carter Newell. The shellfish are grown on long ropes dangling into the water from a raft (top). The ropes are hoisted onboard (bottom), and Newell cuts a mussel open to check for health (middle). Credit: Peter Essick
As one wild fishery after another falters, the future of Maine—and, some say, the future of seafood—may lie in aquaculture, the cultivation of aquatic plants and animals. Historically, intensive fish farms have been linked to a lot of bad things: declines in biodiversity, habitat loss, the overuse of antibiotics, and animal welfare abuses, especially in Asia and Latin America. And in recent years fish die-offs and other problems have plagued North American sites. But Newell represents a new breed of scientist with innovative approaches to growing fish that are both economically and environmentally sustainable. His kludgy mussel-growing apparatus generates three times as much seafood as traditional mussel farms. And because free-floating mussel larvae seed the ropes naturally and eat whatever phytoplankton drifts their way, Newell’s farms require no human-generated feed or energy, a boon for the environment as well as for his bottom line.
A far more controversial experiment in Maine involves cultivating finfish such as salmon and yellowtail either in immense net pens in the ocean or, more recently, in land-based operations where thousands of metric tons of fish circle gigantic tanks like felons pacing around a prison yard. Fish in these recirculating aquaculture systems (RAS) consume a steady diet of scientifically designed feed and, if need be, infection-fighting drugs. The current they swim against is artificially generated, as is the LED light that bathes them up to 24 hours a day to hasten their growth. It is a surreal scenario, but proponents claim RAS are well positioned to bolster Maine’s economy while serving the nation’s growing demand. “The U.S. runs an enormous seafood deficit,” says microbiologist Deborah Bouchard, director of Maine’s Aquaculture Research Network, noting the country relies heavily on fish imported from other nations. “Maine is building on the opportunity to fill the gap.”
Oceanographer David Townsend, director of the School of Marine Sciences at the University of Maine, says the state has two important attributes for fish cultivation: cold, nutrient-rich water and extremely vigorous tides that distribute those nutrients throughout the water column. “Our coastal waters are very productive,” he says.
But the farming of large, carnivorous fish makes some scientists uneasy. Recirculating tanks require huge amounts of energy to move and filter millions of gallons of water daily, and that water still holds waste that can pollute nearby rivers and estuaries. Also, there’s a matter of the fish and their welfare. “Farming finfish on an industrial scale is like farming livestock on land on an industrial scale,” says economist Rosamond L. Naylor, who directs the Center on Food Security and the Environment at Stanford University. “There are ways to minimize risks, but they are costly, and not everyone is taking the steps they should be taking.”
The question of whether industrial aquaculture will enrich Maine’s economy without damaging its fragile ecosystems haunts scientists, politicians and residents. The Gulf of Maine is the least alkaline body of water on the Atlantic coast between Mexico and Canada, and its delicate chemistry is particularly vulnerable to disruptions both natural and human caused. Whatever their outcomes, Maine’s experiments will set an important precedent for seafood production around the globe.
Credit: Accurat (Alessandro Zotta and Alessandra Facchin); Source: FAO Yearbook of Fishery and Aquaculture Statistics 2019. FAO, 2021, accessed March 2022 (data). These charts do not include data for marine mammals, crocodiles, corals, pearls, mother-of-pearl, sponges and aquatic plants.Scientists agree that the food supply must increase substantially to feed the world’s growing population and that cultivated fish, shellfish and algae will play a major role in that expansion. Aquaculture is already the world’s fastest-growing sector of food production, churning out more than half of all fisheries products, and seafood is the most traded commodity on the planet. But although Americans eat a lot of seafood, relatively little is homegrown: an estimated 65 to 85 percent of fish bought for consumption in the U.S. is imported, most of it from China. The U.S. does not export much farmed fish, either, because it grows so little of it. According to the most recent data, from 2019, the U.S. produced 490,000 tons of farmed fish, barely a rounding error compared with the roughly 49 million tons produced by China.
Maine’s Atlantic salmon could help the U.S. compete. Often called the “king of fish,” salmon are sleek, shiny and beautiful. They are also an extremely popular menu item, ranking second only to shrimp as America’s favorite seafood. The cold-water fish were once plentiful in Maine, but dams, overfishing, parasites and pollution all led to the closing of the state’s wild Atlantic salmon fishery in 1948, and today it is illegal to catch or sell them. Today more than 95 percent of Atlantic salmon sold in the U.S. is foreign-grown, most in net pens anchored just below the surface in coastal waters.
Open fish pens have been used in Norway since the 1960s and are still in use in Canada and Chile, but environmental concerns have led to bans in most U.S. coastal states. A ban in Washington, which goes into effect in 2025, will leave Maine as the only state that still sanctions their use. Despite rigorous regulations, every year net-pen operations are cited for environmental and labor-related malfeasance, infestation by sea lice and other parasites, and infectious disease. Scientists say an equally vexing challenge is posed by renegade fish that escape the pens and mate with wild salmon to produce offspring that are genetically ill-equipped to survive. This last threat is especially concerning in Maine, home of the nation’s last remaining wild Atlantic salmon population.
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