Introduction
In British Columbia (BC), Atlantic salmon farming has been around since the early 1970s and is now located in the discovery islands and Vancouver island (Smart,2020). However, these farms are highly controversial In BC due to the perceived nature of biological impacts on the BC ecosystem. Currently, there is a
mandate to eliminate open pen fish farming from the discovery islands in BC waters by 2025 due to their close location to wild salmon runs in BC (Bennet,2020). In this op-ed piece, I seek to understand and disseminate the good, the bad, and the ugly nature of BC salmon farms.
The Good
Salmon farms contribute to around 1.5 billion CAD annually and employ about 7000 British Columbians directly, with indirect benefits (related to the supply of goods and services) and induced effects (when the direct and indirect generated incomes are spent and re-spent in the broader economy) (BC Salmon Farmers, 2021). Aquaculture also has the youngest workforce in Canada, which helps young workers find employment (BC Salmon Farmers, 2021).
The Bad
One criticism of salmon farms is that salmon as predators require at least some fishmeal to sustain themselves and grow big enough for consumption. The fishmeal can come from various places, but much of the fishmeal comprises small pelagic fish, damaging ecosystems (Naylor et al., 2000). Imperial estimates suggest that around 1.2 kg of feed is required to get 1kg of salmon in fish farms (The Fish Site,2011).
The Ugly
Another big area of contention is the disease and parasites that farmed salmon can bring into an area and potentially interact with wild salmon (Krkosek et al., 2006). Sea lice affect both wild and farmed salmon (Vollset et al., 2016).
A recent article conducted by (Mordecai et al., 2021) has also suggested that a virus Piscine orthoreovirus-1 (PRV-1), was brought over he
re by farmed Atlantic salmon and from Europe and the eastern Atlantic. This virus causes circulatory disorders in salmon populations, leading to mass die-off events of farmed species such as Atlantic salmon (Adamek et al., 2019). However, despite claims from this recent study, many previous Department of Fisheries and Oceans investigations have shown little evidence that PRV has transmitted from farmed to wild salmon (Meissner, 2021).
Another ugly factor of salmon farms is the suggested chemical (antibiotics, antifoulants, and pesticides) and nutrient runoff (from excess food and salmon feces) (WWF,2021).
Excess nutrients from feces combined with agricultural runoff and sewage discharge can lead to nutrient loading and eutrophication through algal growth, lowering dissolved oxygen levels leading to marine life die-off events (NOAA,2021) (Mcnevin,2021). In addition, the chemicals used in salmon farms can release toxic compounds into marine areas and species, and both nutrient loading and chemicals in the surrounding waters can affect native salmon populations (Milewski, 2001).
Overall, it is to be seen how BC salmon farming is affected over the next few years with legislation and policy, its safe to say that economically the farms contribute a lot but biologically and socially factors are a little more complicated. I am sure that the controversy surrounding Atlantic salmon farms from stakeholders will continue until the provincial and federal government rule what’s next for the industry.
References
ADAMEK, M., HELLMANN, J., FLAMM, A., TEITGE, F., VENDRAMIN, N., FEY, D., RIßE, K., BLAKEY, F., RIMSTAD, E. & STEINHAGEN, D. 2019. Detection of piscine orthoreoviruses (PRV-1 and PRV-3) in Atlantic salmon and rainbow trout farmed in Germany. Transbound Emerg Dis, 66, 14-21.
BC Salmon Farmers. 2021. Economic Impact. Accessed on the 4th of June 2021 from https://bcsalmonfarmers.ca/economic-impact/.
Bennet., N. Feds order salmon farms shut down by June 2022. Western Investor. Accessed on the 3rd of June 2021 from https://www.westerninvestor.com/british-columbia/feds-order-salmon-farms-shut-down-by-june-2022-3832669.
The Fish Site. 2011. The fish feed story. Accessed on the 7th of June 2021 from https://thefishsite.com/articles/the-fish-feed-story
Meissner., D. Farmed fish the source of virus spread among wild salmon, BC study suggests. Canadian Press. Accessed on the 9th of July from https://www.cbc.ca/news/canada/british-columbia/bc-salmon-virus-study-1.6041776.
KRKOSEK, M., LEWIS, M. A., MORTON, A., FRAZER, L. N. & VOLPE, J. P. 2006. Epizootics of wild fish induced by farm fish. Proc Natl Acad Sci U S A, 103, 15506-10.
Meissner., D. Farmed fish the source of virus spread among wild salmon, BC study suggests. Canadian Press. Accessed on the 9th of July from https://www.cbc.ca/news/canada/british-columbia/bc-salmon-virus-study-1.6041776.
MILEWSKI, I. Impacts of Salmon Aquaculture on the Coastal Environment : A Review. 2001.
MORDECAI, G. J., MILLER, K. M., BASS, A. L., BATEMAN, A. W., TEFFER, A. K., CALETA, J. M., DI CICCO, E., SCHULZE, A. D., KAUKINEN, K. H., LI, S., TABATA, A., JONES, B. R., MING, T. J. & JOY, J. B. 2021. Aquaculture mediates global transmission of a viral pathogen to wild salmon. Science Advances, 7, eabe2592.
NAYLOR, R. L., GOLDBURG, R. J., PRIMAVERA, J. H., KAUTSKY, N., BEVERIDGE, M. C. M., CLAY, J., FOLKE, C., LUBCHENCO, J., MOONEY, H. & TROELL, M. 2000. Effect of aquaculture on world fish supplies. Nature, 405, 1017-1024.
Smart., A. Fish farms on key BC salmon migration route to be phased out by 2022. The Canadian Press. Accessed on the 3rd of June 2021 from https://globalnews.ca/news/7530159/fish-farms-on-key-b-c-salmon-migration-route-to-be-phased-out-by-2022/
VOLLSET, K. W., KRONTVEIT, R. I., JANSEN, P. A., FINSTAD, B., BARLAUP, B. T., SKILBREI, O. T., KRKOŠEK, M., ROMUNSTAD, P., AUNSMO, A. & JENSEN, A. J. 2016. Impacts of parasites on marine survival of Atlantic salmon: A meta‐analysis. Fish and Fisheries, 17, 714-730.
