Geoduck Looks NSFW but Is Prized for Its Flavor

The geoduck is a bivalve mollusk, meaning it has two shells, but what really sets it apart is its long, fleshy siphon. (It's easy to see where its nickname of "elephant clam" comes from.)

This siphon, which extends up to 3 feet (0.9 meters) beyond its shell, is used to filter water and collect nutrients from the water column. The clam itself is quite large, with shells measuring up to 8 inches (20 cm) across, making it a heavyweight in the mollusk world.

Geoducks are known for their soft, pale-colored bodies and thick shells, which are often rough and ridged. Their siphon cannot retract fully into the shell, giving the geoduck its distinct and unusual appearance. It is a true wonder of the marine world.

While all wild geoduck clams are bivalves, there are actually a handful of species with slight variations that appear all around the world.

Geoducks are not particularly social creatures, but they do tend to live in dense colonies, burrowing into the sandy or muddy seabed. This clustering provides some protection from predators, as their extensive burrows and lengthy siphons make them difficult to access, even when you dig deep during low tides.

While they don’t interact much with their neighbors, geoducks contribute significantly to their ecosystem by filtering large volumes of water. This filtering helps maintain the health of the marine environment by cycling nutrients through the water column.

The geoduck is a filter feeder, meaning it draws in water through its siphon and extracts tiny plankton and organic particles for the sustenance they need. As the clam filters water, it also helps improve the clarity and quality of the surrounding environment.

Its diet consists entirely of microscopic organisms found in a water column, making it an essential part of the marine food web. This simple yet effective feeding strategy allows geoducks to thrive in their nutrient-rich habitats.

Geoducks are native to the coastal waters of the Pacific Northwest, particularly Puget Sound, but they can also be found from Alaska to Baja California and on other continents, as we explored earlier in this article.

These clams prefer sandy or muddy substrates, where they can burrow deeply — sometimes up to 3 feet (0.9 meters) into the seabed. They live in intertidal and subtidal zones, ranging from shallow waters to depths of over 300 feet (91.4 meters).

Their habitats are carefully managed by organizations like the Department of Fish and Wildlife and the Department of Natural Resources to ensure sustainable populations, especially in light of geoduck farming and wild harvest practices.

The life cycle of a geoduck begins as a tiny larva drifting in the water column. After a few weeks, the larva settles on the seabed and begins burrowing into the substrate.

As a juvenile, it quickly grows its shell and siphon, reaching sexual maturity within a few years.

Geoducks have extraordinarily long lifespans, with some individuals living up to 150 years. They reproduce by releasing eggs and sperm into the water, where fertilization occurs externally.

A single geoduck can produce millions of eggs in its lifetime, but only a small fraction survive to adulthood.

Geoducks are not currently endangered, but their populations are closely monitored due to their economic and ecological importance. Overharvesting, habitat degradation and pollution have been concerns in areas like Puget Sound, where geoducks are a valuable resource.

Efforts by the Department of Natural Resources and Fish and Wildlife Service focus on sustainable harvesting practices and habitat protection. These measures ensure that geoducks remain a thriving part of the marine ecosystem and an iconic species of the Pacific Northwest.

We created this article in conjunction with AI technology, then make sure it was fact-checked and edited by a HowStuffWorks editor.