June 20, 2018
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Researchers cultivating arctic surf clams in Maine mud flats, hope to create interest among sushi lovers

By Tim Cox, BDN Staff

BEALS, Maine — If you have a taste for sushi, you may have dined on some morsels of the arctic surf clam. Large, adult arctic surf clams have a sizeable purple-colored foot that, when harvested and removed, turns a reddish color. It is prized in Asian markets for an ingredient in sushi.

Brian Beal, professor of marine ecology at the University of Maine-Machias and director of research at the Downeast Institute on Great Wass Island in Beals, has his eyes on the arctic surf clam, but for a different reason.

Beal is leading a research project to determine if the species can be grown in eastern Maine’s lower intertidal mud flats, and if so, whether a market can be developed for arctic surf clams that are 1¼ to 1¾ inches long.

The arctic surf clam is a boreal species, found in the subarctic region of the Northern Hemisphere. They live on the ocean floor, 100-200 feet deep. It inhabits the waters of Alaska, Canada and Maine. They range as far south as Cape Cod in Massachusetts, although in deep water, according to Beal.

“The reason they’ve become a species of interest for consumers,” said Beal, discussing the project at the institute’s research facilities on Wednesday, is because of a Japanese market for a similar species, the Japanese surf clam. Harvested off the coast of Japan, it is has the same kind of purple foot as the arctic surf clam.

“That is the reason why we’re sitting here,” said Beal, pointing to a picture he quickly found in an Internet search for images of the Japanese surf clam. The Google search produced dozens of images of the clam, especially images of the reddish-purplish foot prepared in sushi.

Commercial seafood and fishing interests began searching for a comparable species to the Japanese surf clam about two decades ago, mainly in Canada, according to Beal. Beds of arctic surf clams were discovered off the coast of Nova Scotia and in the Gulf of St. Lawrence, and the Canadian government authorized harvesting. They are sold in Asian markets around the world.

The red surf clam meat is on the menu — hokkigia — at an oriental restaurant in Ellsworth, said Beals. Although he does not eat sushi, Beal tried the dish. He described it as “very mild, very chewy … not quite as delicious as raw scallop meat, but it’s pretty close.”

As popular as the feet are for sushi, it is not Beal’s primary interest. For one reason, feet of the size used in sushi come from clams that take more than 20 years to grow.

“That is not our intention at all,” said Beal.

He wants to be able to raise the clams in the wild to a size that is big enough where the red coloration occurs in the mantle — the tissue along the edge of the shell — and the siphon or neck. The coloration has an appeal in the eye of consumers.

“What we want to do is use the power of the red-footed surf clam at the level of the sushi bar … to use that information to create a nonexisting market — in this case, for the whole clam.”

Beal’s interest is trying to develop markets for the clams when they are less than 2 inches long. Adult arctic surf clams may reach 3½ to 4 inches long, but to attain that growth takes 20-30 years.

Market studies would follow if research shows the clams can be successfully grown in eastern Maine mud flats. The clams potentially could provide ingredients for sushi products or be used whole, such as steamed clams, suggested Beal.

The research is being funded by a two-year, $600,000 grant from the National Science Foundation and a one-year, $100,000 grant from the University of Maine.

Beal has two collaborators, Christopher Davis, executive director of the Maine Aquaculture Innovation Center in Orono, and Sandra Shumway, a professor of marine science at the University of Connecticut. The Downeast Institute is growing the clams and doing some field work.

Beal’s project is building on the work of other researchers in the 1990s, notably Davis, who studied hatchery techniques for cultivating arctic surf clams.

“It was his idea at the time to develop techniques that we’re using now at DEI … to produce these animals,” said Beal.

Beal and the institute also have a commercial partner in the research, Albert Carver’s nearby business, AC Inc.

“We’re working with Albert and his crew to learn more about the culture outside the hatchery for growing these,” said Beal, and growing some arctic surf clams in his company’s lobster pounds.

Kevin R. Athearn, a resource economist at the University of Maine-Machias, will be working with AC Inc. in order to try to develop markets for the clams.

At Downeast Institute, marine shellfish-ecology technician Cody Jourdet is duplicating the work Davis did in the 1990s and using it to grow arctic surf clams for field testing.

“It’s a very difficult enterprise,” said Beal. “It takes a lot of hard work.”

The arctic surf clam is “not a species that cultures very well,” added Beal, and requires cold water most of the time. “Cody has had to do some reinventing” of the methods pioneered by Davis, he said, and has developed some of his own techniques. Part of the work of culturing the clams involves growing nine to 10 species of algae.

“The things that we’ve found and are really excited about [is] … they can grow in mud flats,” said Beal. He noted that they do not have to be 200-300 feet below the surface of the ocean. The research also has shown that the clams will over-winter in some of the coldest temperatures — such as those experienced this past winter.

Last year, arctic surf clams were grown in mud flats in Cutler. Half of them were removed in the fall, but the other half were left in place until last month.

“We had excellent survival over the winter,” said Beal.

The clams were grown in a tidal area where they would be out of the water for two to three hours twice a month for several days at a time, what Beal termed “stressful and harsh conditions.” The results showed that conditions in Washington County are suitable to grow arctic surf clams to a commercial size, he said.

“However … the survival rate is not what we need,” said Beal. The objective would be a survival rate of 70 percent to 80 percent for clams from ¼ inch to ½ inch in size. The survival rate so far is about 20 percent because the clams have been preyed upon by green crabs, even when protected by netting.

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