December: The "Other" Mollusks

Chesapeake Almanac Podcast Episode and Transcript

Episode 37
Copyright © John Page Williams, Jr. all rights reserved.

This is John Page Williams with another reading from Chesapeake Almanac. The month is December and this one is entitled, "The 'Other' Mollusks."

Clams in the Chesapeake are not widely known. Two different species,the soft shell clam or mano and the hard clam, are harvested commercially, but most of the catch is shipped outside the Bay. Mannoes grow best up the bay and hard clams down, so people in different sections of the Bay country have different pictures of what the word clam means. To confuse the situation more, there's several other species of clam and their closely related mussels that are not harvested by man to any great extent. Even so, these relatively unknown mollusks play important roles in their own communities.

Whenever Joe and Ilia Fehrer paddled their canoe on the upper Pocomoke, which was quite often, they always kept their eyes out for shells on the bank. The river's freshwater clams are food for otters and raccoons, who carry them up onto the banks to pry or bite them open. These Unio clams are also called freshwater mussels. They live in loose mud, and they taste like it, so they have little value as food for humans. But they once were harvested across the eastern United States for their pearly inner shells, which were cut into buttons. Plastics put an end to the trade, and now the animals are back to their relative safety of obscurity, but also to their extremely important job of filtering water just the way oysters do. The freshwater sections of most of the Bay's tidal rivers grow a wide range of freshwater mussels, but that's a story for another time.

In the low and medium salinity sections of the rivers lives the brackish-water clam, Rangia cuneata. The animal lives in both sand and mud, and it tends to take on the taste of the bottom area in which it's living. Sometimes that's clean sand, in which case the clam has a good taste, and I've known, I've had friends who have cheerfully harvested them and steamed them. River-wise humans gather these with quiet smiles, steam them, and eat them with relish. Most of the Rangia clams, though, live in mud, and so have little to fear from man. Seagulls take to them, however. They pick up larger clams, fly aloft, and drop them onto hard services to crack them. The bayside parking lot of the Northrop Grumman Oceanic Division research laboratory, at the western end of the Bay Bridge, is littered with fragments of Rangia shells.

This clam is to be admired for its adaptability. It lives well in low salinities, and it can tolerate turbid water that would suffocate other clams. When tropical storm Agnes hit the Chesapeake in June 1972, it drastically lowered the salinity of the whole system and poured in millions of tons of sediment. Many of the Bay's clams died, but the conditions that killed them spread the Rangia clams into places where they'd not lived before. That winter, waterfowl returning to the Bay from Canada found wrecked aquatic vegetation and clam bars, but they also found beds teeming with small Rangia. Over the next couple of winters, the Rangia population grew, and the clams became a staple in the diet of several waterfowl, especially canvasback ducks and tundra swans.

Waterfowl swallow small clams whole and grind them up in their gizzards. In addition to the canvasbacks and swans, diving ducks like scoters and oldsquaws consider clams and small mussels staple foods. Two particularly important species are Macoma balthica, a small, soft shell clam that lives best at medium and high salinities, and Ischadium recurvum, the hooked mussel, which lives in the same salinities and attaches to firm substrates like oyster shells and pilings. In warm weather, both species are also important to bottom-feeding fish, especially spot and croakers, who dig them out and swallow them wholesale. Open the intestinal tract of a big spot from the lower Bay, and chances are there will be enough shell fragments in there to pave a road. It is remarkable that the fragments don't damage the intestines as they pass through.

One other mollusk deserves mention, and that is the ribbed mussel, which often lives half-buried in the banks of salt marshes. This animal filters food from the water at high tide and closes tightly as the water drops, to avoid drying out.

A mussel attaches to its substrate by a bundle of strong threads called a byssus. The threads are made of keratin, a tough protein fiber which also occurs in human hair. Byssell threads are so tough that, in Brittany, fisherman's wives used to knit their husbands' work gloves from those of the blue mussel, a relative of the ribbed mussel much esteemed for its flavor and native to Europe and New England. The ribbed mussel will never support a great market, but it is edible and worth gathering for steaming. Anyone who does so will realize just how strong the byssus is. The ribbed mussel is most important in the Bay as a favorite winter food for raccoons living around the salt marshes and also for its filtering capacity.

The Chesapeake's most sporting clam is the stout razor. Digging it is a pursuit that expends more calories than the digger gets from eating it. Stout razors live in sand or firm mud. One can harvest them from the shallow flats where they live by looking for holes on the surface and then digging into the burrows below. That is most easily done when low tide uncovers the flats. It sounds simple—no equipment needed but a human body. But stout razors are tricky. They are generally 12 to 18 inches deep to begin with, and they can dig fast. The digger, then—the human—kneels on the mud and begins digging with one hand down into the burrow. With luck, it would be possible to get three or four fingers around the clam and, with gentle pressure, force it to release its hold on the mud. But sometimes the digger can get only a couple of fingers onto the clam—not enough to pull with. And sometimes a clam will just keep on digging, leaving the pursuer up to the armpit in the hole, fingers grasping only watery mud. Stout razors live in medium and high salinities on flats around salt marshes, in places like Tangier Sound, Gwynn's Island, and Poquoson. Digging them means getting wet and muddy, so it's best done in a bathing suit in warm weather, but that means greenhead fly season. It is painful to have one arm stuck down a burrow while half a dozen greenheads go to work on your back. Digging stout razor clams requires a sense of humor.

One serious caution: there may be shell fragments with sharp corners buried among the burrows. Moving a hand suddenly could cause a deep cut that might require stitches. We speak from experience. So before digging, check a flat carefully for broken shells in any case. Digging stout razors will cause small nicks in the fingers. It's a good idea to rub these with a thin coating of antibacterial ointment to minimize infection and speed healing.

After all this, stout razors are often gritty. Put them into a pan of fresh Bay water with a cup of cornmeal and set them in the shade for an hour or so. Then steam them and eat them with melted butter. They are an aesthetic exercise from start to finish, but that is the way a sporting proposition should be.

In the end, many of the Chesapeake's clams live their lives with minimal human interference. They are, however, vital members of the Bay community. Consider, though, what their cumulative filtering effect is on the health of the Bay's waters, and also what a ribbed mussel is worth in late November to a hungry raccoon trying to keep its body temperature up on a cold night, or a Macoma clam to a young canvasback duck exhausted by its migration from the Saskatchewan prairies. Studying a less well-known member of the Bay community is often a good window to understanding it better.

For more happenings around the Bay in December see our other Chesapeake Almanac podcasts and read our blog posts "Buffleheads and a Winter Miracle" and "Getting Outside in December."

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