The Geoduck: The Planet's Most Uniquely Shaped Mollusk

If you've ever come across the term geoduck, you might have imagined it referred to a duck with a penchant for cartography. Unfortunately, that couldn't be further from the truth. Pronouncing it as gee-oh-duck is also incorrect. While a geography-loving duck might be called gee-oh-duck, this saltwater clam is properly pronounced "gooey duck." And no, they are neither gooey nor ducks.

Geoducks are, in fact, the largest burrowing clams in the world, typically weighing between 2 to 2.5 pounds (0.9 to 1.1 kilograms). Unlike the giant clam, which is mostly shell, the geoduck's shell is modest compared to its expansive soft body. The term geoduck originates from a Nisqually Tribe word meaning "dig deep."

Digging Deep

The name is fitting, as these clams embed themselves 2 to 3 feet (0.6 to 0.9 meters) deep in mud, sand, or gravel on the ocean floor. Within 48 hours of hatching, the tiny clams develop a foot to dig into the mud. Once settled, they remain there for life. They inhabit the northern regions of the Pacific Northwest, from Puget Sound through British Columbia and into Alaska. Natural "beds" are found on many public beaches, though they are rarely visible except during extremely low tides.

As they mature, the siphon (the neck protruding from the shell) and the mantle (the "breast meat" inside the shell) function as both gills and a mouth. While siphons and mantles are common in shellfish, the geoduck's are too large to fit inside its shell. They leave the mantle exposed at the mud's surface while burying their shells deep below. There, they feed, breathe, and thrive for up to a century.

By around 15 years of age, geoducks reach their full size. Their shells rarely exceed 8 inches (20 centimeters) in width, but their necks can stretch over 3 feet (1 meter) long. They often live beyond 100 years, with scientists using the rings on their shells to study climate change over decades. The oldest recorded geoduck lived to 168 years, and the largest, discovered in Discovery Bay, Washington, weighed over 8 pounds (3.6 kilograms).

Digging In

For centuries, geoducks have been a staple in the diets of northwestern Native Americans, enjoyed either fresh or smoked. Today, native tribes continue to harvest them, holding treaty rights to half of the shellfish harvest in Washington state's Puget Sound.

Geoduck harvesting is strictly regulated to avoid overharvesting. These clams are highly sought after beyond the Pacific Northwest, with most being exported to China. In Hong Kong, a single geoduck can fetch up to $60, and prices sometimes soar to $150. The combination of limited supply and high demand has led to incidents of clam theft and smuggling. Meanwhile, geoduck farming is gaining traction as a legal and sustainable alternative.

For shellfish enthusiasts, geoducks offer a familiar yet sweeter and crunchier taste compared to other clams. The siphon, the edible part, is particularly abundant in geoducks. To prepare for cooking, detach the siphon from the shell and stomach, remove the skin, and slice it thinly. Geoducks are often lightly sautéed in stir-fries to maintain their texture and flavor. They can also be eaten raw, as in sushi, or enjoyed traditionally, as the First Nations of the Pacific Northwest have done for generations.