Panopea generosa

The Pacific geoduck (“gooey-duck”; ; Panopea generosa ) is a species of very large saltwater clam in the family Hiatellidae. The common name is derived from the Lushootseed (Nisqually) word gʷídəq.

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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 centimetres (6 in) to over 20 centimetres (8 in) in length, but the extremely long siphons make the clam itself much longer than this: the "neck" or siphons alone can be 1 metre (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 168 years old.

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Animal name origin

The name geoduck is derived from a Lushootseed (Nisqually) word gʷídəq either a word composed of a first element of unknown meaning and əq meaning "genitals" (referring to the shape of the clam), or a phrase meaning "dig deep", or perhaps both, as a double entendre. 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 pong ). A group of geoducks is called a "bag".

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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.

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Popular culture

Evergreen State College in Olympia, Washington, has a geoduck as its mascot named Speedy.

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Geoducks have also earned some internet infamy due to the phallic appearance of their siphons.

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Habits and Lifestyle

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, but specimens weighing over 7 kilograms (15 lb) and as much as 2 metres (6 ft 7 in) in length are not unheard of.

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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 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 168 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.

Geoducks are broadcast spawners. A female geoduck produces about 5 billion eggs in her century-long lifespan. However, due to a low rate of recruitment and a high rate of mortality for geoduck eggs, larvae, and post-settled juveniles, populations are slow to rebound. In the Puget Sound, studies indicate that the recovery time for a harvested tract is 39 years.

Biomass densities in Southeast Alaska are estimated by divers, then inflated by twenty percent to account for geoducks not visible at the time of survey. This estimate is used to predict the two percent allowed for commercial harvesting.

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Diet and Nutrition


Ecological niche

Geoduck farming grow-out and harvest practices are controversial, and have created conflicts with shoreline property owners, and concerns from nongovernmental organizations. However, the Environmental Defense Fund has found that bivalves (oysters, mussels, and clams) are beneficial to the marine environment. The water must be certifiably clean to plant geoducks commercially. Regulation was mandated in 2007. Studies have been funded to determine short- and long-term environmental and genetic impacts. In southern Puget Sound, the effect of geoduck farming on large mobile animals is ambiguous. A 2004 draft biological assessment, commissioned by three of the largest commercial shellfish companies in the Puget Sound region, identified no long-term effects of geoduck farming on threatened or endangered species.


1. Geoduck Wikipedia article -

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