Geoduck

The Pacific geoduck (/ˈɡuːiˌdʌk/ GOO-ee-duk; Panopea generosa) is a species of very large saltwater clam in the family Hiatellidae. The common name is derived from the Lushootseed name, gʷidəq.

The geoduck is native to the coastal waters of the eastern North Pacific Ocean from Alaska to Baja California. The shell of the clam ranges from 15 centimeters (6 in) to over 20 centimeters (8 in) in length, but the extremely long siphons make the clam itself much longer than this: the "shaft" or siphons alone can be 1 meter (3 ft 3 in) in length. The geoduck is the largest burrowing clam in the world. It is also one of the longest-living animals of any type, with a typical lifespan of 140 years; the oldest has been recorded at 179 years old. The precise longevity of geoducks can be determined from annual rings deposited in the shell which can be assigned to calendar years of formation through crossdating. These annual rings also serve as an archive of past marine variability.

The name Geoduck is derived from the Lushootseed name for the animal, gʷidəq. The etymology of gʷidəq is disputed. According to a published dictionary of Lushotseed, the lexical suffix =əq means "many." The Oxford English Dictionary says it is composed of a root word of unknown meaning and assigns to =əq the meaning "genitals" (referring to the shape of the clam), while other researchers say it is a phrase meaning "dig deep".

It is sometimes known as a mud duck, king clam or, when translated literally from Chinese, an elephant-trunk clam (Chinese: 象拔蚌; pinyin: xiàngbábàng; Jyutping: zoeng6 bat6 pong5).

Between 1983 and 2010, the scientific name of this clam was confused with that of an extinct clam, Panopea abrupta (Conrad, 1849), in scientific literature.

Native to the west coast of Canada and the northwest coast of the United States (primarily Washington and British Columbia), these marine bivalve mollusks are the largest burrowing clams in the world, weighing in at an average of 0.7 kilograms (1+1⁄2 lb) at maturity. The largest ever weighed and verified by Washington Department of Fish and Wildlife biologists was an 8.16 pounds (3.70 kg) specimen dug near Adelma Beach in Discovery Bay.

A related species, Panopea zelandica, is found in New Zealand and has been harvested commercially since 1989. The largest quantities have come from Golden Bay in the South Island where 100 tonnes (110 short tons) were harvested in one year. There is a growing concern over the increase of parasites in the Puget Sound population of geoduck. Whether these microsporidium-like parasitic species were introduced by commercial farming is being studied by Sea Grant. Research to date does indicate their presence.

The oldest recorded specimen was 179 years old, but individuals usually live up to 140 years. A geoduck sucks water containing plankton down through its long siphon, filters this for food and ejects its refuse out through a separate hole in the siphon. Adult geoducks have few natural predators, which may also contribute to their longevity. In Alaska, sea otters and dogfish have proved capable of dislodging geoducks; starfish also attack and feed on the exposed geoduck siphon.