Let’s talk salmon farming

Since the dawn of time, the human mind has been in constant motion—constantly developing new practices and tools that change the lives of humans and their environments for better or for worse. For instance, fishing techniques have changed immensely throughout the years. During the Paleolithic era, harpoons were utilized. Soon after, nets were revolutionized. Many other innovations followed. Recently, salmon farming is an innovation that has come to replace caught wild salmon with farmed salmon. This technique has proved to be more convenient, efficient, and profitable, able to raise huge amounts of salmon to accommodate the increasing human population.

However, in recent years, this practice has also been widely criticized for its negative environmental and economic impacts including habitat modification, pollution, resource exploitation, and decreasing biodiversity. Since salmon farming involves raising salmon in enclosed paddy-like pools, pesticides and antibiotics are usually required for maintenance. As a result, water inside the enclosure often becomes contaminated, leaking into  nearby water sources as well. Maintenance also requires a high demand of fish feed—a product derived from small pelagic species of fish. As more small pelagic species of fish are caught to produce fish feed, biodiversity declines. Another drawback occurs when nearby aquatic species become endangered due to the introduction of non-native fish species.

Despite these consequences, there seems to be no denying the profitability and efficiency of salmon farming. Robert Rhew, an associate professor at University of California at Berkeley who specializes in environmental sciences, suggests that salmon farms offer “the promise of cost-effective and sustainable fisheries, if done correctly.” Currently, humans are still on the search for profitable and effective innovations to make salmon farms sustainable.

One such innovation is inland farming, a practice involving raising salmon in land-based facilities. Several companies have adopted this practice to produce fish. In a fish farm located in West Virginia, “salmon and steelhead trout [are raised] in low-salinity water hundreds of miles from either species’ natural habitat.” By raising salmon in locations far from natural habitats, risks concerning the escaped farmed salmon becoming an invasive species to wild fish species in the natural habitat. In 2017, the escape of approximately 200,000 Atlantic salmon from a Washington fish farm raised concerns that the “Atlantic salmon will outcompete Chinook salmon for food, breed with them to create hybrids, or spread diseases like sea lice.”

Even in Maine, the largest producer of farmed Atlantic salmon in the U.S., has plans to establish an inland salmon farm that would “produce more than 60 million pounds of salmon per year.” This amount is nearly doubled that of Maine’s typical production “between 18 and 35 million pounds of fish per year.” Thus, inland salmon farming is not only sustainable but also has the potential to be more efficient and profitable than conventional salmon farming.

Figure 1: Asian carp – an invasive fish species. Inland farming is a method of preventing invasive species from escaping.

Inland salmon farming has also expanded internationally. Japan is “testing a new technique to grow on land, in a mountainous region near Tokyo, in hopes of being able to produce fish profitably away from the sea that surrounds Japan” (“New Technique Tested”). British Columbia established an inland farm for sockeye salmon. British Columbia is also home to Kuterra, an inland salmon farm known for its sustainable practices. Inland farming is a practice that is expanding globally. Its appeal has reached a global audience due its sustainability and profitability.

Other innovations making salmon farming sustainable include new approaches to water treatment. The reverse osmosis (RO) process involves producing “potable water from brackish water and seawater in order to reclaim contaminated water sources and to reduce water salinity for industrial applications.” In addition, the RO process can be wind-driven—“being able to treat and recycle aquaculture wastewater using renewable energy, making it suitable in remote areas where electricity was hard to obtain.” Thus, this approach offers a more sustainable and efficient water treatment method compared to using chemicals. Pollution is especially of concern if “salmon farm are treated with antibiotics or other chemicals.” Currently, chemicals are the typical water treatment method in salmon farms. However, certain chemicals are toxic and contaminate the environment. The RO process provides a nontoxic and safe water treatment method that can also be practical in energy-deficient areas.

Integrated aquaculture systems are another approach towards the progress for sustainable salmon farming. An integrated aquaculture system involves having “two or more ecologically compatible species in one system; they can co-inhabit an environment with no conflict in food and space.” Integrated aquaculture systems offer a method of maintaining the practice of salmon farming while also farming other species. The selected species are those that will not endanger the salmon but rather provide nutrient or reuse waste in the ecosystem. In this case, salmon farms accumulate large amounts of waste. This excess waste could provide fertilizer for seaweed. With this method, pollution will not be an issue as waste is consumed by other organisms.

Figure 2: With the compatible species in the same enclosure, a balanced ecosystem is formed so that “wastes of one resource consumer become a resource (fertilizer or food) for others in the system.”

Conventional salmon farming typically carries negative impacts for the environment. For instance, the 2017 Atlantic salmon escape in Washington proved how catastrophic these salmon farms can be. Pollution and habitat modification are some of the consequences of salmon farms. Fortunately, humans are currently developing new innovations to fix these issues. Nevertheless, salmon farm and other types of aquaculture are significant sources of food for the growing human population. In the words of Dr. Rhew, “If salmon farms are to continue, they need to adopt [the] best practices and be high regulated.” The development of sustainable approaches and technology will benefit aquatic species and human species—both of which rely on the earth for sustenance and shelter.



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Associated Press, 22 Mar. 2018.

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Shawn Tran

Shawn is a second-year student with an intended major in Public Health and a minor in Chinese. He is a native of Sacramento – the city of trees and capital of California. His interests include hiking, traveling, spending time with family, and learning different languages and cultures. Through joining SERC Blog, he hopes to bring awareness to important environmental issues and topics. Shawn Tran covers aquaculture and environmental economics.

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