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Adult geoduck generally have separate sexes and broadcast spawn usually during summer (Andersen 1971, Sloan & Robinson 1984, Campbell & Ming 2003). 1998a, Bradbury & Tagart 2000, Hand & Bureau 2000) with annual landed values varying between 32 and 42 million Canadian dollars in British Columbia during 2000 to 2003. abrupta in Washington State, British Columbia and Alaska (Campbell et al. 1984) from California to Alaska and to southern Japan (Coan et al.

This geoduck species is distributed in coastal areas from the intertidal zone to at least 100 m (Jamison et al. The Pacific geoduck clam, Pare)pea abrupta (Conrad, 1849), is a large hiatellid bivalve found buried up to 1 m within mud and sand substrates. KEY WORDS: geoduck, Panopea abrupla, density, recruitment, growth In plots where there was low exploitation and geoduck densities remained similar over lime, ] values also remained similar, but k values varied with time suggesting other biologic or environmental factors could have influenced growth rates. After removing many old individuals from a geoduck population, the mean maximum asymptotic length (]) of the you Bertalanffy growth model decreased, and the Brody growth function k values increased. Recruitment was similar between plots after high and low exploitation rates, suggesting thai fishing and different geoduck densities had no long term effect on subsequent recruitment. In two plots that had high exploitation in the first 3 years, the geoduck population densities and the average age (by removing old individuals) were substantially reduced, but thereafter densities slowly increased due to geoduck recruitment. abrupta, in 0.25 ha experimental plots with controlled fishing in two areas of southern British Columbia over a 9-year period. The shells are fewer in kinds, lacking the bright colors, but occur in great numbers.ABSTRACT Information was presented on the density, recruitment to harvestable size, and growth of the Pacific geoduck clam, P. Because of harsh coastal conditions, most gastropods do not do well here.

The Pacific geoduck clam shown above is part of the Oregonian Province: "The cool-water Oregonian Province along the Pacific Northwest Coast lies between the frigid Aleutian Province of Alaska and the warmer Southern Californian and Panamic Provinces. They are especially common in the post-Paleozoic fossil record. The fossil record of bivalves is Cambrian to Recent. Some groups are hard substrate encrusters, using a mineral cement to attach to rocks, shells, or wood.

In hard substrate environments, some forms make borings, in which the bivalve lives. The majority of bivalves are infaunal - they burrow into unlithified sediments. Most of them are filter-feeders, using siphons to bring in water, filter the water for tiny particles of food, then expel the used water. Bivalves are also known as pelecypods and lamellibranchiates.īivalves are sessile, benthic organisms - they occur on or below substrates. They occur in marine, estuarine, and freshwater environments. In most bivalves, the two shells are mirror images of each other (the major exception is the oysters). Panopea generosa Gould, 1850 - Pacific geoduck clam (public display, Bailey-Matthews Shell Museum, Sanibel Island, Florida, USA)īivalves are bilaterally symmetrical molluscs having two calcareous, asymmetrical shells (valves) - they include the clams, oysters, and scallops. Panopea generosa (Pacific geoduck clam) 1