The most impressive clam in the Pacific Northwest is the geoduck (Panopea generosa). The world's largest burrowing clam, the geoduck reaches an average size of 2.07 pounds (including the shell) in subtidal waters of Puget Sound (based on surveys of commercial beds before fishing). The average size of recreationally caught geoducks on intertidal public beaches in Puget Sound is 2.47 pounds. The largest geoduck ever weighed and verified by WDFW biologists was a 8.16-pound specimen dug near Adelma Beach in Discovery Bay in year 2000. Much larger specimens have been reported by commercial harvesters. Geoducks grow rapidly, generally reaching 1.5 pounds in three to five years. They attain their maximum size by about 15 years, and can live at least as long as 168 years. They are extremely abundant in the inland waters of Puget Sound, British Columbia and Alaska, where the subtidal populations support important commercial fisheries. Their range extends from Alaska to Baja California, but they are rarely found along the Pacific coast, and populations are likewise scarce west of Clallam Bay in the Strait of Juan de Fuca. Geoduck clams are found buried two to three feet deep in mud, sand, or gravel. The gaping, oblong shell is white with concentric rings, and generally has thin patches of flaky brown covering (periostracum) at the edges. The siphon and mantle are so large that they cannot be withdrawn into the shell.
Geoducks have been observed with underwater video cameras living as deep as 360 feet in Puget Sound, and the vast majority of the population is subtidal. They are not nearly as abundant intertidally, and sport diggers generally find them on beaches only at extreme low tides (lower than -2.0 feet). For this reason, most of the sport digging is restricted to less than 20 tides a year.
The clam's name, pronounced "gooey-duck" is of Native American origin and means "dig deep." It is variously spelled goeduck, goiduck, or gweduck.
|Two geoducks (6.53 pounds and 5.19 pounds) dug by WDFW divers near Discovery Bay. The bigger of the two is known as "Moby". Photos by Kristina Wilkening.
||Digging a geoduck.
Natural "beds" of geoducks exist on many public beaches in Washington, but they will seldom be exposed except at tides lower than about -2.0 feet. Only Puget Sound and Hood Canal contain abundant populations of geoducks; they are rarely encountered on the Pacific coast beaches and west of Clallam Bay in the Strait of Juan de Fuca. The most popular geoduck beaches include:
The best places to watch experienced geoduck diggers capturing these big clams are Duckabush and Dosewallips State Park. Visit How to Dig Geoduck and get some tips on how to dig your first geoduck. You can also learn a lot by going to a popular beach during an extreme low tide and watching the "experts."
You'll also want to watch "Three Feet Under," a documentary film produced and directed in 2002 by Justin Bookey, and available in DVD. This award-winning film includes not only practical tips on digging geoducks, but a wealth of historical, scientific, cultural and comic insights into the King of Clams.
The Evergreen State College in Olympia adopted the geoduck as its official mascot, along with the motto Omnia Extares ("Let it all hang out").