The Pacific Oyster
By Christopher Ballard
Keywords: British Columbia, Aquaculture, Oyster, Invasive, Climate Change
Summary
The importance and difficulties of Pacific oyster aquaculture in British Columbia, especially in the Comox Valley region, are covered in this case study. Issues such as biodiversity loss, environmental impact, and the effects of climate change are addressed while highlighting advantages like job creation, economic growth, and nutritional value. It is emphasized how vital Pacific oysters are to aquaculture worldwide and how advantageous the conditions are in the Strait of Georgia in British Columbia. Nonetheless, it highlights the detrimental impacts on regional biodiversity, particularly in the Comox Valley, a hotbed for the shellfish aquaculture industry. Ecological genealogy reveals how Pacific oysters introduce non-native species, change water quality, and impact native species like the Olympia oyster. The contribution of eelgrass beds to the biodiversity of marine ecosystems is also covered. Currently, oyster farming communities are addressing the effects of climate change, confronting threats posed by invasive species, and considering socioeconomic factors in today’s context. As we move into the future, it is recommended that we invest in climate change adaptation for sustainable aquaculture, support Indigenous economic opportunities, manage invasive species, and implement ecosystem-based management. This case study aims to highlight the necessity of flexible tactics, community engagement, and legislative support to strike a balance between business interests and environmental preservation in BC's Pacific oyster aquaculture sector.
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Ecological geneaology
In British Columbia, the aquaculture of Pacific oysters has greatly benefited people by generating jobs, expanding the variety of seafood available, and boosting local coastal communities. With oysters being a good source of protein and other necessary nutrients, farmed oysters enhance human health and wellbeing. In addition to contributing to tourism and jobs, the industry bolsters the local economy. Although Pacific oyster aquaculture has proven to be beneficial for humans, there are significant drawbacks to the surrounding environment. First off, there is a decline in biodiversity as a result of Pacific oysters outcompeting native species for the same niche. Due to their quick development and abundant procreation, dense oyster reefs may form, altering the surrounding environment and upsetting normal biological processes (Herbert, R. J., et. al., 2016). The Olympia oyster (Ostrea lurida) was the sole native oyster in British Columbia before European settlers arrived. Indigenous peoples have harvested and utilized it since time immemorial. After the arrival of settlers in coastal BC, Olympia oysters were overharvested, with populations being decimated as a result of further development and the introduction of Pacific oysters (Ridlon, A. D., et al., 2021). Given the filter-feeding nature of Pacific oysters, these organisms can cause changes in water quality, impacting nutrient cycling, which leads to an increase in nutrients and frequency of algal blooms (Miossec, L., Deuff, R. M. L., & Goulletquer, P., 2009). The Pacific oyster has a much larger calcium carbonate shell than the native Olympia oyster, which would ultimately increase the amount of minerals in the environment over time (Padilla, D. K., 2010). Furthermore, as a result of the human impact of the aquaculture projects, this would allow for the further introduction of non-native species by means of netting and ballast ships down the line (Mach, M. E., Levings, C. D., & Chan, K. M., 2017). A vital component of improving marine ecosystem biodiversity is eelgrass beds. Numerous marine animals, such as fish, invertebrates, and birds, rely on eelgrass meadows for food and shelter. These habitats support algae and other microorganisms, playing an essential role in multitrophic interactions (Mach, M. E., Levings, C. D., & Chan, K. M., 2017). Additionally, the complex root systems of eelgrass enhance water clarity and stabilize sediments, which promotes the growth of other aquatic plants and improves the general health of the ecosystem. Presently, the largest farming operations of Pacific oysters in British Columbia come from Baynes Sound in the Comox Valley, and it is safe to say that the coastline has undergone significant changes through time.
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present tense
Presently, Pacific oyster aquaculture in the Comox Valley is confronted with a number of challenges that involve social and ecological aspects. This sector, which contributes to the economy, is facing difficulties that could jeopardize its resilience and sustainability. The growing frequency and intensity of climate change impacts on oyster farming operations is one of the main causes for concern. Climate change exacerbates the stresses already affecting oyster aquaculture, including rising sea temperatures, changing weather patterns, and ocean acidification. These elements have a direct impact on the growth, survival, and reproduction of oysters, which reduces yields and results in economic losses. Sudden weather extremes like heat waves and storms, such as those experienced during the 2021 heat dome event, further jeopardize the stability of the industry. Other invasive species seriously threaten the aquaculture of Pacific oysters. Both the introduced Pacific oyster and the native Olympia oyster can be preyed upon, have their resources outcompeted, or have diseases introduced by non-native species like the Japanese oyster drill and the European green crab (Buhle, E. R., & Ruesink, J. L. 2009). These invasions have been shown to cascade through ecosystems where species composition and natural processes have been disrupted, thus affecting ecosystem dynamics. Understanding the difficulties facing Pacific oyster aquaculture requires an awareness of social and cultural factors. The decline in oyster yields due to other invasive species and climate change threatens the economic stability of many coastal communities. Many coastal communities depend on oyster farming for their livelihoods, but not all places are created equal. In wealthier nations like Canada, research has been done on the effects of Pacific oysters on eelgrass beds, while less wealthier jurisdictions lack access to this type of funding (Martínez‐García, M. F., et al., 2022). Furthermore, traditional knowledge and practices related to oyster farming are deeply ingrained in the identities of many coastal communities since the introduction of the Pacific oyster in BC’s waters (Martínez‐García, M. F., et al., 2022), giving oyster farming cultural significance. These communities may experience social and cultural upheaval if environmental pressures disrupt their customs and means of subsistence. Ultimately, it is important to find a balance between the social-cultural and economic benefits of Pacific oyster aquaculture and the impact that these oysters have on ecosystems going forward.
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future tradjectory
The future trajectory of Pacific oyster aquaculture production will hinge on several important factors. The first is the management of invasive species in BC waters. This encompasses steps to control and eliminate populations of invasive species, as well as early detection and quick response programs. One species of note would be Didemnum vexillum, a tunicate that can smother native habitats, including oyster beds and rocky reefs, leading to biodiversity loss and ecosystem degradation (Ferguson, L., et. al., 2017). Another approach to adopt moving forward is the introduction of ecosystem-based management strategies that take into account how ecological, social, and economic factors are interconnected when making decisions about aquaculture in British Columbia (Ridlon, A. D. et al., 2021). This entails adopting a comprehensive perspective on the resilience and health of ecosystems, integrating ecosystem services into the planning of aquaculture, and supporting ecosystem-based adaptation techniques. When it comes to Indigenous communities, many have species fishing rights on their traditional territories regardless of species; therefore, exploring economic opportunities for indigenous peoples would be beneficial. Moving forward, given the importance of the oyster aquaculture industry, it would be necessary to invest in adaptation plans to lessen the effects of climate change on oyster farming. As a direct result of climate change, Pacific oysters are able to spread northward and inhabit areas that may not have been considered suitable otherwise (King, N. G., et al., 2021). Mitigation measures would have to be put in place to limit the spread of Pacific oyster populations where they are not present. To ensure resilience to environmental change, other steps might entail implementing novel methods of oyster farming that can withstand environmental stressors, such as selective breeding for resistance to heat and acidification. As a result of extreme weather events, this would threaten the survival of oysters as a direct result of them happening more frequently, making populations harder to sustain. In order to reduce risks and increase the efficacy of conservation aquaculture programs for the Olympia oyster and other endangered marine species, adaptive management techniques intertwined with traditional ecological knowledge need to be emphasized. (Ridlon, A. D., et al., 2021). Understanding the picture moving forward is essential to ensuring the biodiversity of the coast of British Columbia is resilient for future generations.
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References
Buhle, E. R., & Ruesink, J. L. (2009). Impacts of invasive oyster drills on Olympia oyster
(Ostrea lurida Carpenter, 1864) recovery in Willapa Bay, Washington, United States. Journal of Shellfish Research, 28(1), 87–96.
Ferguson, L., Davidson, J., Landry, T., Clements, J., & Therriault, T. (2017). Didemnum
vexillum: invasion potential via harvesting and processing of the Pacific oyster (Crassostrea gigas) in British Columbia, Canada. Management of Biological Invasions, 8(4), 553–558. https://doi.org/10.3391/mbi.2017.8.4.10
Herbert, R. J., Humphreys, J., Davies, C. J., Roberts, C., Fletcher, S., & Crowe, T. P. (2016).
Ecological impacts of non-native Pacific oysters (Crassostrea gigas) and management measures for protected areas in Europe. Biodiversity and Conservation, 25, 2835–2865.
King, N. G., Wilmes, S. B., Smyth, D., Tinker, J., Robins, P. E., Thorpe, J.,... & Malham, S. K.
(2021). Climate change accelerates range expansion of the invasive non-native species, the Pacific oyster, Crassostrea gigas. ICES Journal of Marine Science, 78(1), 70–81.
Mach, M. E., Levings, C. D., & Chan, K. M. (2017). Nonnative species in British Columbia
eelgrass beds spread via shellfish aquaculture and stay for the mild climate. Estuaries and Coasts, 40, 187–199.
Martínez‐García, M. F., Ruesink, J. L., Grijalva‐Chon, J. M., Lodeiros, C., Arreola‐Lizárraga, J.
A., de la Re‐Vega, E.,... & Chávez‐Villalba, J. (2022). Socioecological factors related to aquaculture introductions and production of Pacific oysters (Crassostrea gigas) worldwide. Reviews in Aquaculture, 14(2), 613-629.
Miossec, L., Deuff, R. M. L., & Goulletquer, P. (2009). Alien species alert: Crassostrea gigas
(Pacific oyster). ICES Cooperative Research Reports (CRR).
Padilla, D. K. (2010). Context-dependent impacts of a non-native ecosystem engineer, the Pacific
oyster Crassostrea gigas. Integrative and Comparative Biology, 50(2), 213-225.
Ridlon, A. D., Marks, A., Zabin, C. J., Zacherl, D., Allen, B., Crooks, J., ... & Wasson, K.
(2021). Conservation of marine foundation species: Learning from native oyster restoration from California to British Columbia. Estuaries and Coasts, 44(7), 1723-1743.
Ridlon, A. D., Wasson, K., Waters, T., Adams, J., Donatuto, J., Fleener, G.,... & Grosholz, E. D.
(2021). Conservation aquaculture as a tool for imperiled marine species: Evaluation of opportunities and risks for Olympia oysters, Ostrea lurida. Plos one, 16(6), e0252810.
(Ostrea lurida Carpenter, 1864) recovery in Willapa Bay, Washington, United States. Journal of Shellfish Research, 28(1), 87–96.
Ferguson, L., Davidson, J., Landry, T., Clements, J., & Therriault, T. (2017). Didemnum
vexillum: invasion potential via harvesting and processing of the Pacific oyster (Crassostrea gigas) in British Columbia, Canada. Management of Biological Invasions, 8(4), 553–558. https://doi.org/10.3391/mbi.2017.8.4.10
Herbert, R. J., Humphreys, J., Davies, C. J., Roberts, C., Fletcher, S., & Crowe, T. P. (2016).
Ecological impacts of non-native Pacific oysters (Crassostrea gigas) and management measures for protected areas in Europe. Biodiversity and Conservation, 25, 2835–2865.
King, N. G., Wilmes, S. B., Smyth, D., Tinker, J., Robins, P. E., Thorpe, J.,... & Malham, S. K.
(2021). Climate change accelerates range expansion of the invasive non-native species, the Pacific oyster, Crassostrea gigas. ICES Journal of Marine Science, 78(1), 70–81.
Mach, M. E., Levings, C. D., & Chan, K. M. (2017). Nonnative species in British Columbia
eelgrass beds spread via shellfish aquaculture and stay for the mild climate. Estuaries and Coasts, 40, 187–199.
Martínez‐García, M. F., Ruesink, J. L., Grijalva‐Chon, J. M., Lodeiros, C., Arreola‐Lizárraga, J.
A., de la Re‐Vega, E.,... & Chávez‐Villalba, J. (2022). Socioecological factors related to aquaculture introductions and production of Pacific oysters (Crassostrea gigas) worldwide. Reviews in Aquaculture, 14(2), 613-629.
Miossec, L., Deuff, R. M. L., & Goulletquer, P. (2009). Alien species alert: Crassostrea gigas
(Pacific oyster). ICES Cooperative Research Reports (CRR).
Padilla, D. K. (2010). Context-dependent impacts of a non-native ecosystem engineer, the Pacific
oyster Crassostrea gigas. Integrative and Comparative Biology, 50(2), 213-225.
Ridlon, A. D., Marks, A., Zabin, C. J., Zacherl, D., Allen, B., Crooks, J., ... & Wasson, K.
(2021). Conservation of marine foundation species: Learning from native oyster restoration from California to British Columbia. Estuaries and Coasts, 44(7), 1723-1743.
Ridlon, A. D., Wasson, K., Waters, T., Adams, J., Donatuto, J., Fleener, G.,... & Grosholz, E. D.
(2021). Conservation aquaculture as a tool for imperiled marine species: Evaluation of opportunities and risks for Olympia oysters, Ostrea lurida. Plos one, 16(6), e0252810.