By Isabella Xu, Winter 2021.

Sushi, fish tacos, and shrimp cocktails are undoubtedly delicious and well known around the world, but the origin and production of the seafood that ends up on our plate rarely crosses our minds. As the human population grows faster than ever, the supply of wild fish is dwindling, which holds significant ramifications for the environment. Currently, the two main methods of obtaining the seafood that we  adore are through catching wild fish and through farming fish. In recent years, there has been a buzz about fish farming, also known as aquaculture, as a way of mitigating the negative effects of overfishing. Despite the rise of fish farming as a potentially more sustainable source of seafood, there are also negative environmental and economic effects of farm seafood that cannot be ignored. However, there is evidence that a focus on innovative fish farming techniques can mitigate some of these problems and allow for more sustainable aquaculture practices.

As the demand for fish and other seafood rises in recent years, the supply of  seafood has had to keep up. One way in which the world’s demand for seafood is met is through fishing  wild stocks, but this has gone to the point where many species are overfished. According to the Food and Agriculture Organization under the United Nations, the number of overfished stocks have tripled over the past 50 years [1]. This means that fishing vessels are catching fish faster than the stocks can replenish naturally through reproduction. Overfishing causes imbalances in the ecosystem, and has the potential to disturb the vulnerable marine species in a food web, such as corals and sea turtles [1]. Furthermore, overfishing can lead to changes in the size, reproductive cycle, and rate of maturity for the remaining fish, which in turn affects the future population of wild caught fish [1]. While overfishing allows fishermen to obtain more fish in the short-term, overfishing threatens jobs and coastal economies that depend on the dwindling stocks in the long run [1]. In this way, not only does overfishing affect the ocean ecosystem, but it also affects many people in coastal communities whose jobs and livelihood rely on the availability of fish. The increased demand for seafood drives overfishing, which can lead to the unnecessary loss of many species such as fish, sea turtles, and crustaceans [1].

         In addition to fishing for wild seafood, fish farming, or aquaculture, is another growing industry to satisfy the demand of seafood. In thinking about seafood farming as an alternative to excessive fishing, we can see myriad benefits to this approach. By farming seafood, we can increase our ability to meet the growing demand for seafood and enhance food security for the growing population [2]. However, aquaculture also has negative effects that aren’t necessarily apparent at first glance. Even though fish farms are located in the water, significant land is taken up to sustain the operation of these fish farms. In a review article published in the Environmental Management journal, it was predicted that aquaculture will occupy 44 million ha of land by 2050 [2]. Furthermore, an estimated 61.6 million ha of land is predicted to be needed to grow the ingredients for aquafeed (i.e. feed for the fish) by 2050 [2].The demand for land for aquacultural use is important to keep in mind particularly because it takes away land that could otherwise be used for farming or residential purposes. 

         Furthermore, habitat destruction is another negative effect of aquaculture that is not evident. In many countries in Asia, the practice of converting rice fields to fish ponds is common due to its profitability [2]. However, this irreversible conversion alters the habitat for many flora and fauna through artificial means, and as such is predicted to have negative impacts on biodiversity in these regions [2]. In a similar vein, mangrove forests in many coastal regions are being converted to shrimp farms due to the lack of regulation [2]. Many plants and animals depend on the mangrove forests as a habitat and these forests provide coastal protection from erosion [2]. In this way, the deforestation of mangroves and the conversion of rice fields to fish ponds cause habitat destruction that can greatly disrupt the local ecosystem.

         Finally, the byproducts of aquaculture are antibiotics, fertilizers, and hormones that run off into the water and cause water pollution [2]. Additionally, intensive fish farming practices, like overstocking and overfeeding fish ponds, can lead to increased production of fish waste products that reduce the quality of the water [2]. Nutrient pollution, also known as eutrophication, leads to algal blooms that kill fish residing near these blooms [2]. Not only does eutrophication lead to decreased water quality, but can also have a significant economic effect in the loss of fish. It is reported that an algal bloom in Japan led to the loss of $330 million worth of fish, and as such, the intensive fish-farming practices must be reexamined in light of negative effects on the environment and economy [2].

         Despite all these potentially negative effects of fish-farming, it should be noted that fish-farming is not inherently harmful to the environment. Rather, specific practices such as overstocking or overfeeding result in these harmful effects. There is indication that aquaculture can occur sustainably with effort and innovation. For example, an offshore fish farm in Panama uses the rushing water to help dilute fish waste and disease, and a farm that produces black cod in British Columbia utilizes scallops, oysters, kelp, and sea cucumbers to consume and filter waste product from the fish [3]. Finally, many fishermen promote sustainability through oyster and kelp farming which reduces the need for aquaculture feed [3]. In this way, with ingenuity and creativity, seafood can be produced in a way that does not cause disease, habitat destruction, or loss of native species in marine environments. As the demand for seafood increases, turning to fish farming could be a more sustainable and viable option in the long run. Despite some of the negative effects of fish-farming, a deliberate focus on technology and innovation can make a significant difference in creating a sustainable industry.

[1] “What Is Overfishing? Facts, Effects and Overfishing Solutions.” WWF. World Wildlife Fund. Accessed February 15, 2021. https://www.worldwildlife.org/threats/overfishing.

[2] Ahmed, Nesar, Shirley Thompson, and Marion Glaser. “Global Aquaculture Productivity, Environmental Sustainability, and Climate Change Adaptability.” Environmental Management 63, no. 2 (2018): 159–72. https://doi.org/10.1007/s00267-018-1117-3.

[3] Bourne, Joel K. “How To Farm a Better Fish.” National Geographic Magazine. Accessed February 15, 2021. https://www.nationalgeographic.com/foodfeatures/aquaculture/.