ECOLOGICAL DATA
Distribution: widespread, in sheltered to moderately
exposed brackish or outer coastal areas.
Habitat: fine mud through sand to gravel; may be abundant in eelgrass; burrows
up to 1 m; planktonic larvae dispersed by currents; adults create semi-permanent burrow.
Tidal elevation: subtidal, from 8 to 120 m depth; may occur in lower
intertidal; occurs higher in intertidal in north coast; most common between 9-18 m
subtidal.
Food: suspension feeder; mainly phytoplankton, but also zooplankton and
detritus.
Predators: sea stars, crabs, fishes, and birds.
GROWTH RATE
Slow; sexually mature by 3 yr; reaches 16 cm in 10 yr, little
change in length in remaining years; may weight up to 4.5 kg.
FISHERY
Largest clam in B.C., supports valuable subtidal commercial,
Native and small intertidal sport fishery; in 1986 commercial harvest was over 5,000 t
valued at $4.3 million; sewage pollution and paralytic shellfish poisoning (PSP) have
closed areas of the coast to harvesting.
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REFERENCES
Anon. (no date). Clams of British Columbia. Fish. Oceans Can.,
leaflet: 4 p.
Breen, P.A., and T.L. Shields. 1983. Age and size structure in five populations of
geoduck clams (Panope generosa) in British Columbia. Can. Tech. Rep. Fish. Aquat.
Sci. 1169: 62 p.
Fitch, J.E. 1953. Common marine bivalves of California. Calif. Dep. Fish Game Fish
Bull. 90: 102 p.
Goodwin, C.L. 1973. Subtidal geoducks of Puget Sound, Washington. Wash. Dep. Fish.
Tech. Rep. 13: 64 p.
Jamieson, G.S., and K. Francis. 1986. Geoducks, p. 18-22. In G.S. Jamieson and
K. Francis. Invertebrate and marine plant fishery resources of British Columbia. Can.
Spec. Publ. Fish. Aquat. Sci. 91.
Quayle, D.B. 1978. The intertidal bivalves of British Columbia. B.C. Prov. Mus. Handb.
17: 84-85.
Ricketts, E.F., J. Calvin, and J.W. Hedgpeth. 1985. Between Pacific tides. 5th ed.
Stanford Univ. Press, Stanford, Calif.: 325-328.
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