The geoduck (\(Panopea\) \(generosa\)) is the world’s largest burrowing saltwater clam and is highly sought after in global seafood markets. Its most striking feature is its exceptionally long siphon, or “neck,” which can extend up to one meter (3.3 feet) from the shell. The geoduck is also one of the longest-living animals on Earth, typically living around 140 years, with some individuals reaching 179 years of age. This long-lived bivalve has specific habitat requirements that dictate where it is found along the Pacific coastline.
Primary Geographic Distribution
The geoduck is native exclusively to the coastal waters of the eastern North Pacific Ocean. The species extends from the southern reaches of Alaska down to Baja California in Mexico. However, the highest population densities and the most significant commercial fisheries are concentrated in the Pacific Northwest.
This core concentration includes the protected waters of Washington State, particularly Puget Sound, and the coast of British Columbia, Canada. While the range stretches north to Kodiak Island, Alaska, and south to Baja California, populations in these extreme limits are more sparsely distributed. The Pacific Northwest offers the most suitable balance of environmental factors, leading to a robust and economically significant presence of the clam.
Essential Habitat Requirements
The survival of the geoduck depends on a precise combination of physical and environmental factors. The clam requires a stable, soft substrate that allows for deep burrowing but provides enough structure to prevent collapse. This ideal sediment is typically composed of a mixture of fine to coarse sand and mud.
Geoducks are strictly marine organisms, requiring full saltwater conditions to thrive. They inhabit a wide range of depths, extending from the very low intertidal zone down into the subtidal zone. Although most abundant in shallower areas, they have been observed at depths exceeding 110 meters (361 feet). The water column must be clean and rich in phytoplankton, as the geoduck is a filter feeder.
The Permanent Burrow: A Lifetime Home
Once the geoduck larva settles on the seabed, it begins a lifelong commitment to a single location by burrowing deep into the substrate. This burrow protects the clam from most predators and environmental disturbances. The clam generally settles at a depth of about 0.3 to 1 meter (1 to 3.4 feet) below the surface.
The shell, which can measure up to 20 centimeters (8 inches) long, remains fixed deep within the sediment, becoming sessile once the clam reaches adulthood. The siphon stretches all the way to the water-sediment interface. This allows the clam to draw in water for respiration and filter feeding while its body remains safely buried below. The geoduck is incapable of re-burrowing if it is removed from the sediment.