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Nature Notes: Atlantic Sea Scallop

Ed Robinson
January 7, 2020

Temperatures are falling and snow is piling up around town. That is great if you are a skier or snowmobiler, but it also spells good news for our dinner table. This is the time of year when one of Maine’s seafood delicacies becomes available to satisfy our cravings. This fishery is also an important contributor to Maine’s marine economy. Of course, I am referring to Placopecten magellanicus, the Atlantic sea scallop.

Atlantic sea scallop (Photo by RLSPhoto iStock)

Another winter seafood delicacy, the tiny and sweet Maine shrimp, is gone from our tables at least through the 2021 season. But the harvest of sea scallops is more than holding its own. This is good news because the scallop, properly handled and fresh on your plate, is a tender, tasty delight that puts often over-cooked bay scallops to shame. Kudos to the fishermen and divers who brave cold winter conditions to harvest sea scallops for the benefit of diners near and far.

The sea scallop has a smooth, rounded shell with a minimum legal diameter of four inches, sometimes reaching 10 inches after as many as 20 years of life (six to eight years is more common where harvested regularly). The shell is variegated in shades from reddish pink to white with a large orange/cream colored adductor muscle that opens and closes the shell (with a diameter between one and three inches).

Europeans generally dine on the whole scallop in its shell. In Maine we eat only the adductor muscle, with fishermen shucking the meat on the boat before landing.

Sea scallops are bivalve mollusks, with two large, oval valves that move water, nutrients and waste products through the scallop.

Like oysters, they can filter many gallons of water each day and remove microscopic plants, bacteria and other organic materials from the water, including pollutants. Bits of seaweed are known to be a part of scallop diets near shore.

The body of the scallop is wedge-shaped and has a large foot. Scallops have a row of fully developed eyes located between the valves.

Predators include cod, flounder, lobsters, seals, crabs, sea stars, whelks and invasive sea worms known as Polydora websteri.

Scallops are prolific breeders, producing millions of eggs in response to the presence of sperm from neighboring scallops. Once the eggs are fertilized, the tiny zygotes are then released into the water, where they sit on the sea floor. The resulting larvae drift or swim in the ocean for several weeks as they feed and begin to develop their eyes, foot and shell. They can swim well into adulthood (four to six years) but tend to settle onto the ocean floor for growth and eventual reproduction.

Such scallops are generally found from Labrador as far south as North Carolina, in depths down to 1,000 feet depending upon water temperatures. As ocean temperatures rise above 68 degrees Fahrenheit, the population of sea scallops will drop off. Adult sea scallops are normally located on bottoms with firm sand, shells, small stones or rocks.

Unlike so many other ocean fisheries, the Atlantic sea scallop population is considered by NOAA, the federal regulatory agency for ocean fisheries, as healthy, with harvests being conducted at a level appropriate to support sustainability. As the largest wild scallop fishery in the world, the US market was valued at $533 million in 2018, the third highest total ever.

A great deal of research and regulatory effort is directed at protecting this important resource in the face of changing ocean conditions and rising demands for healthy seafood. The key players are the National Marine Fisheries Service, the New England Fishery Management Council and Maine’s Department of Marine Resources. Massachusetts and New Jersey represent the two biggest harvesters of sea scallops. Approximately 600 licensed Maine fishermen report just two percent of total US landings.

Across their range, sea scallops are harvested in several ways, from large offshore boats that journey to the Georges Bank and beyond for a week or more to day boats working close to shore. In Maine, professional divers harvest scallops in dry suits to survive winter’s icy waters. From December to April, the harvest is strictly controlled and there are limits on the areas to be fished, the number of days on the water and the quotas for the catch.

The bulk of the US harvest comes aboard via large dredges that are pulled along the ocean floor and are designed to pick up as few undersized scallops as possible. Environmentalists have challenged the practice of dredging, out of concern that repeated movement over the ocean floor is damaging to many other creatures. A Gulf of Maine Research Institute report on sea scallops states, however, that preliminary research studies conducted on Georges Bank suggest the bottom substrates in scallop producing areas are able to recover from moderate dredging because these resilient habitats have adapted to naturally unsettled environmental conditions.

Maine fishermen are working in state waters within three miles of shore. We have an advantage in landing highly prized diver scallops because our waters are cold enough to allow scallops to thrive in shallow, near shore waters.

There is growing interest in farming sea scallops, similarly to oysters. This practice is well established in places like Japan, and delegations from Maine have visited there to learn the techniques. Scallops can be raised in open bottom beds, bottom-located cages, floating cages or suspended from lines in what is called “ear hanging.” Scallops grown by ear hanging are expected to grow faster, reaching maturity in two to three years, and they may have fewer predators when not living on the ocean floor.

Numerous surveys and actual buying decisions in the marketplace demonstrate that American consumers are increasingly interested in quality farm-raised seafood, and are willing to pay higher prices if the food is raised in a sustainable manner. The Seafood Watch group from the Monterey Bay Aquarium has raised consumer awareness of problems with pollution, unlicensed chemical usage and slave labor in major Asian seafood producing sectors. New scallop farming techniques may allow Maine harvests to take place during most of the year, rather than just the winter months, addressing currently unmet needs for fresh product.

Unlike so many other Atlantic fisheries, the sea scallop is holding its own in part thanks to careful monitoring and control of harvests. In 1950, the reported landings of scallops in Maine totaled 524,800 pounds of meat. The harvest rose and fell during the following decades but after the turn of the century, harvests fell as much as 90 percent. Starting in 2009, regulators and fishermen adopted new management strategies to protect the resource, with fewer permits issued, a higher minimum harvest size and rolling closures of areas to allow regeneration. This approach seems to have worked well, with the 2018 Maine harvest reported at 563,363 pounds and regulators projecting similar harvests for the 2020 and 2021 seasons.

As we have seen in other fisheries (e.g. lobsters, oysters), Maine scallops have a strong appeal in the marketplace given our clean water and the scallops’ excellent flavor. Chefs in white tablecloth restaurants clearly favor scallops from Maine, and the boat prices paid to fishermen have been very strong as a result.

Whether served raw as sushi grade or prepared gently broiled with delicate sauces, Maine sea scallops are a delight to the palate. They are also healthy seafood, providing a low fat, high protein option that contains essential nutrients such as vitamin B12, selenium, zinc and small amounts of omega-3 fatty acids to aid heart health. As long as you don’t pour on the butter and binge on the white wine, you can feast on sea scallops all winter without guilt!

Look for local scallops at the Veggie Corner on Harpswell Neck Rd or at Gurnet Trading Post on Route 24 in Brunswick!

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