Environmental Risks and Impacts of Geoduck Aquaculture
As noted above, Geoduck cultivation started in BC over twenty years ago; however the scope of these operations has been small (Fisheries and Oceans Canada, 2014). The province currently has the capacity to expand its geoduck aquaculture sector, however many concerns remain about potential impacts of these practices on the environment and wild geoduck, and the commercial fishery they support (Marshall, McKinley, & Pearce, 2012). There is significant need for more research in this area since academic literature remains sparse. Nevertheless, based on the scientific evidence garnered about other large scale shellfish aquaculture activities - namely mussels, clams, and oysters - inferences can be made about the potential effects that may stem from more intensive geoduck cultivation (Straus, Crosson, & Vadopalas, 2009).
First of all, geoduck cultivation may affect the underlying substrate (Straus, Crosson, & Vadopalas, 2009). Like other bivalves, geoduck clams release both pseudo-feces and feces into the surrounding environment that may change the composition of the substrate, increasing nutrient and organic content. Secondly, adult geoducks feed on phytoplankton through filter feeding (Feldman, et al., 2004). Aquaculture significantly increases geoduck densities in contrast to wild stock densities, which may reduce the amount of phytoplankton remaining in the water column for other species consumption. A potential way to mitigate phytoplankton depletion is to restrict cultured geoduck densities. However, a benefit of increasing the amount of filter feeding in a given area is the reduction of inorganic particles (Straus, Crosson, & Vadopalas, 2009). This may have a positive ...
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...tions (Zhang & Hand, 2006). Variability is key to ensuring survival in the face of natural and anthropogenic stresses (Feldman, et al., 2004). Although larvae dispersal during the planktonic life stage may sustain some genetic diversity within the greater meta-population, human culture of organisms generally lead to selection of ‘ideal’ broodstock. Paired with higher densities of juveniles reared from a hatchery, and the fact that harvesting will occur after reproductive age is reached, genetic diversity may be lessened. Therefore, it is of utmost importance that broodstock is collected from the same area it will be seeded, is reselected every year, and a variety of specimen are selected.
More research is needed to ensure long term sustainability of the geoduck aquaculture industry and monitored to ensure there are impacts to the environment are not significant.