Are Clams Overharvested?

Clams - The All Purpose Bivalve

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Over the past thirty years, worldwide consumption of seafood has exploded. Species at the top of the food chain, such as cod, tuna and some types of sharks, are known to be at risk of collapse (in the case of cod) or facing a decades-long recovery process.

 Attempts to limit catch and bycatch meet with fierce local opposition, as in recent battles between small-boat commercial fishermen and NOAA regulators in New England. Government numbers can always be challenged by the fluctuations inherent in any species’ numbers over time. Sometimes populations rebound for no apparent reason and without new regulation. Nevertheless de facto extinction for some popular seafoods is now a possibility due to overfishing. The extermination of the dodo bird and the passenger pigeon are still relevant. Clams are as popular these days as ever, and still easy to dig. Is the American clam population at risk?

Because no reliable estimate of total clams is possible, a surrogate indicator is total clam consumption over time. In 2000, total US seafood consumption was 15.6 pounds per person per year. Clams are #7 on the list of top ten seafood types, at about a half-pound per person per year. According to the Yearbook of Fishery Statistics, the soft-shell or steamer clam, Mya arcenaria, had a take rate between 5190 and 5113 metric tons over the period 1994 through 1999, the most recent data available. This indicates a roughly stable population as well as stable US harvesting practice. US consumption of the hard-shell clam Mecenaria mercenaria varied from 21855 metric tons to 4631 metric tons from 1994 through 1997, indicating a much less stable population, vulnerability to disease, change in harvest practice, seasonal fluctuations, greater consumer interest or any combination of these. The number of variables that bear on seafood take rates can make interpreting consumption rates difficult. However, the relative instability of the hardshell clam consumption rate relative to soft-shell clams at least suggests the latter may be at risk.

A recent archeological discovery of human remains in an Iowa sewer proves North Americans have been consuming clams for at least seven thousand years, according to Archeology Daily News. Shell heaps around the world attest to shellfish’s ease of harvest and reliability as a food source for Stone Age hunter-gatherers. Tens of thousands of clams are taken daily from our waters, and devoured in households and restaurants nationwide. Can the sweet, tender flesh of the clam survive modern technology and its success at meeting man’s growing interest in shellfish?

So far we can say yes. No variety of clam is today listed either as Endangered or Threatened by the US Fish and Wildlife Service. But one thing is sure: as industrial development continues to accelerate worldwide, new standards will be needed to protect clam beds from runoff and septic contamination. The recent steps toward improved sewage pollution treatment to comply with modifications to the Clean Water Act are steps in the right direction.

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