Geoducks.
The geoduck, Panopea
abrupta, is a species of very large saltwater clam, a
marine bivalve mollusk in the family Hiatellidae.
The shell of this clam is large, about 15 to over 20 cm
in length (about 7 to 9 inches), but the extremely long
siphons make the clam itself very much longer than this:
the "neck" or siphons alone can be one meter
in length.
Native to the northwest coast of the United States and
Canada (primarily Washington and British Columbia), the
geoduck is the largest burrowing clam in the world, weighing
in at an average of one to three pounds (0.5–1.5
kg) at maturity, but specimens weighing over 15 pounds
(7.5 kg) and as much as 2 meters (6 ft) in length are
not unheard of. 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.
Geoducks are one of the longest-living organisms in the
Animal Kingdom. They have a life expectancy of about 146
years, with the oldest recorded at over 160 years. Scientists
speculate that the geoduck's longevity is the result of
low wear and tear. A geoduck sucks plankton down through
its long siphon, filters them 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... |
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