Don't Forget About Clams, the Other Sustainable Shellfish
Clams, along with oysters, scallops, mussels, and cockles, are bivalve mollusks, meaning that they have two symmetrical shells held together with a ligament and a hinge. They’re not only good for you and easy on the environment but sweet-briny in flavor, easy to cook, and versatile. What’s not to love?
A three-ounce serving (85.04 grams) of steamed clams contains 22 grams protein, 4 grams carbohydrates, and less than 2 grams fat (if you forgo the melted butter). In addition to 18 milligrams of vitamin C (30 percent of the daily value based on a 2,000-calorie diet), as well as vitamins A and B12, calcium, potassium, selenium, and zinc, that same portion will yield 24 milligrams of iron (133 percent of the daily value)—good to know if you’re at risk for anemia and want to avoid red meat or supplements.
Many people are trying to eat more seafood for the omega-3 fatty acids, which may offer protection against heart disease, possibly stroke, and even autoimmune diseases such as rheumatoid arthritis. Three ounces of steamed clams provide 117 milligrams EPA and 174 DHA. One big plus—especially for children, and women of child-bearing age or who are pregnant—is that clams are free from high levels of mercury, unlike tuna, say, or many lake fish.
One caveat: If you’re watching your salt intake, you should be aware that clams are naturally high in sodium; three ounces contain 1,022 milligrams and 57 milligrams cholesterol.
According to the Monterey Bay Aquarium Seafood Watch, “farmed or hand-harvested clams are a ‘Best Choice’ worldwide, since the impact on habitats and other sea life is minimal. Clams harvested with hydraulic dredges are a ‘Good Alternative’ because there's some concern about the impact of this catch method on the seafloor, even when used on a sandy habitat.”
Most of the clams available today at fish markets and supermarkets are farmed, and if you happen to live on the East Coast, odds are they come from one of the hardest-working suppliers in the seafood trade, H.M. Terry Co., on the Eastern Shore of Virginia, the finger of land that separates the Chesapeake Bay from the Atlantic Ocean. The family business, established in 1903, supplies millions of Sewansecott clams to the Atlantic Seaboard annually, and along with JC Walker Brothers and Shooting Point Oyster Company, also on Virginia’s Eastern Shore, they know the key to success is the purity of the waters they farm. Within the 80-mile chain of barrier islands of the Virginia Coast Reserve, those waters are designated and protected as a United Nations Biosphere Reserve.
Depending on where you live, here’s what you may find at your local fish market.
From the Atlantic
Atlantic Hard-Shell Clam (Mercenaria mercenaria)
This clam, which is also known as a quahog (pronounced "KO-hog," and more about that in a sec) can grow to 4 inches or more in diameter at the hinge. It’s sold under different market names, depending on grade (size/age), region, and producer. H.M. Terry, for instance, produces three grades: middle necks, which are 1 to 1½ inches (7 to 9 per pound); littlenecks, which are 7/8 to 1 inch (9 to 12 per pound); and so-called pasta necks, which are 5/8 to 7/8 inch (12 to 15 per pound).
You may see littlenecks (originally from Little Neck Bay, on Long Island, New York) from other suppliers as big as 1½ or 2 inches, though, and other options include cherrystones, which originally hailed from the Eastern Shore’s Cherrystone Creek and range from 2 to 3 inches or so. Sometimes a small cherrystone is called a top neck. Chowder clams are the largest Atlantic hard-shells, and they’re what are known as quahogs in New England.
Got all that? The important thing to remember is that, generally speaking, the smaller the clam, the more tender it is. Littlenecks are typically served raw on the half-shell or steamed; large clams are often chopped and stuffed for baking or made into chowder. Fun fact: This clam’s Latin name, mercenaria, is derived from the use of the shell for making wampum, or Native American money. Beads that were made from the purple splotch on the smooth inside of the shell were the most valuable form of wampum.
Mahogany Clam (Arctica Islandica)
This small ocean quahog is wild-harvested from Maine’s coastal waters and is stronger-tasting than other Atlantic clams. You may see it labeled “black clam” or the trademarked “Golden Neck.”
Atlantic Soft-Shell Clam (Mya Arenaria)
The term “soft-shell” is a bit of a misnomer as this clam does have a hard shell; it’s just thinner and more brittle than that of an Atlantic hard-shell clam. This type is usually referred to as a steamer and is readily identified by its protruding, funky-looking tube, which is two connected siphons (for respiration and feeding). Because the tube prevents the bivalve from closing its two shells completely, steamers are more perishable than the clams mentioned above. Check for freshness by touching the tube lightly; it should retract slightly.
Atlantic Razor (AKA Jackknife) Clam (Ensis Directus)
One look at the long, narrow, sharp-edged shell of this clam will tell you how it got its name, and it shouldn’t be confused with the wider, meatier West Coast razor clam (see below). Atlantic razor clams steamed in a garlicky black bean sauce are a perennial favorite at many Chinese restaurants.
From the Pacific
Manila Clam (Tapes Philippinarum)
This hard-shell clam, which is native to the waters of Japan, China, Korea, and the Philippines, was accidentally introduced to the West Coast of the United States and Canada in the early 20th century, and it’s become extremely popular. It’s a small clam, 1¼ to 2 inches in diameter, but because the shells are thinner (although not as thin as those of steamers), you get more meat per clam than from other similarly sized hard-shells.
Pacific Littleneck Clam (Protothaca Staminea)
This hard-shelled clam, native to the West Coast, resembles the manila and is less expensive. It tends to be tougher, though, and can be tricky in the kitchen because when you steam a pound or so, the individual clams take longer to cook and won’t all open at the same time. Freezing them in the shell briefly (about five minutes) helps them cook more consistently.
West Coast (AKA Pacific) Razor Clam (Siliqua Patula)
This razor clam, a specialty of the Pacific Northwest, is broader, larger, and more robust in flavor than the Atlantic razor. James Beard was a huge fan; his mother sautéed them in butter or made them into fritters or chowder. Yum.
New Zealand Cockles (Austrovenus Stuchburyi)
Cockles are very similar to clams, and most of the ones we see in the U.S. are sustainably farmed in New Zealand. With their distinctive green-tinged shells, they turn everyday linguine with clam sauce into something with more panache.
In the Kitchen
If the shells of a hard-shell clam are agape before cooking, squeeze them together. If they remain closed, you’re good to go. If the shells spring apart when the pressure is released, don’t eat the clam. After cooking, discard any clams that have not opened.
As far as recipes go, it’s hard to go wrong with baked clams oreganata, steamed clams in wine and chorizo, or even a quick, cut-to-the-chase paella. In cold weather, however—the temperature is plummeting as I write this—I crave a good chowder. Which I need to go shop for right now.