The next time you sit down to a steaming bowl of clam chowder, consider this: your meal may be older then you are. Much, much older.

Indeed ocean quahaugs, often used in chowder, are probably the longest-lived animals on the planet. Earlier this year, researchers dredged up a 405-year-old quahaug from the frigid waters off Iceland. They did not eat it.

They named it Ming, after the Chinese dynasty which ruled at the time the clam first settled into the sediment. For those more comfortable with comparisons to European and American history, 1602 was the year Queen Elizabeth I died. It marked the first performance of Shakespeare’s Twelfth Night. It was the year Bartholomew Gosnold became the first white man to see Cape Cod.

While a clam 405 years old is unusual, it is likely there are others even older out there, according to a British researcher, Paul Butler of Bangor University in Wales, who was part of the expedition which found it. Several other ocean quahaugs as ancient have been dredged up, and individuals of 200 years or so are not uncommon.

And they’re not just in Icelandic waters, but also in the waters near here.

“There are long-lived quahaugs out there as well,” he said.

“The record from the eastern seaboard of the U.S. is about 220 years. It looks as if they live longer in Iceland, but we don’t really know.”

And why does it matter, anyway, that these clams live so long?

For two reasons, Mr. Butler said. The first, and the primary interest of the research expedition, is that they could provide clues to climate change.

The age of the clams can be gauged by measuring growth rings — which radiate out from the hinge of the quahaug toward the lip — much as with trees. Differences in the patterns of banding could give clues to environmental changes.

“We do seem to have a correlation at least for the Iceland shelves with a temperature signal [although] that’s based on very preliminary data,” he said.

“We know that animals growing in the same area show the same patterns with the banding, which can only be due to a common environmental influence.

“The real difficulty is to tease that influence out.”

The study was primarily carried out on behalf of the European Union, as part of efforts to determine climatic variation over the past 1,000 years or so.

But the team also received funding from a British charity, Help the Aged, whose concern is with older people and who fund research into the aging process.

The ocean quahaugs seem to have some mechanism that slows the cell breakdown which eventually kills us all.

Now, it needs to be said, lest you feel uncomfortable chowing down on these geriatrics of the animal kingdom, that they are a different species from those you are likely to eat in fresh chowder here on the Vineyard.

But that is not to say you might not have eaten them, most likely in canned chowder. They were first harvested during World War II from waters off Rhode Island. About 2,000 tons of meat was produced by the East Coast fishery until about 1976, but, as stocks of the other, more palatable type of quahaug declined, the ocean quahaug catch increased, peaking at around 20,000 tons in 1996. The most recent figures show about 13,000 tons of shucked meat.

The fishery is closely regulated, given their growth rates (they are also among the slowest-growing marine organisms) and low reproduction rates (females may not reach sexual maturity in some cases until they are more than 60 years old).

As one academic paper on the distribution, biology and management of the species records: “Large ocean quahaugs . . . have relatively small, dark and tough meats which prevent their use as clam strips or in higher valued products [and] are used in processed clam products such as soups, chowder and sauces. Landings of smaller ocean quahaugs from Maine waters are marketed as mahogany clams, sold on the half-shell market or for steaming.”

Rick Karney, shellfish biologist and director of the Martha’s Vineyard Shellfish group, said these quahaugs were most often put in red chowder, made with a tomato rather than a cream base, which better disguised their inferior flavor and dark color.

The quahaugs you are likely eat around here are usually around 10 to 15 years old, or maybe 40 or 50 for a “real big honker,” Mr. Karney said.

Still pretty old for a food item, but it’s not like eating history.