How Marine Farming is Dewilding the Ocean and its Inhabitants: A Q&A with Laurie Sellars and Becca Franks

A new study by Laurie Sellars, postgraduate fellow of the Law, Ethics & Animals Program at Yale Law School, and Becca Franks, an assistant professor of environmental studies at New York University, investigates how marine aquaculture or ‘mariculture’ — the cultivation of aquatic organisms in the ocean — generates a suite of risks: environmental degradation, harms to wildlife communities and individuals, welfare harms for captive animals, and shifts in how humans perceive the nonhuman world. The article describes these risks collectively as “dewilding,” defined as the process of privileging anthropocentric interests, perspectives, sovereignty, and agency at the expense of other interests and considerations The study, “How Mariculture Expansion is Dewilding the Ocean and its Inhabitants,” was published in the journal Science Advances on Oct. 16, 2024. Sellars and Franks discuss their research.

Compared to terrestrial systems, mariculture systems are less common. Why did you feel it important to examine mariculture given that its current footprint is proportionately small compared to terrestrial systems?

Sellars: Though mariculture currently has a smaller global footprint than terrestrial animal agriculture does, aquaculture as a whole — across all modes of cultivation, e.g., coastal and freshwater — is one of the world’s fastest growing food systems. Production of farmed aquatic organisms has soared since 1990, and projections by the Food and Agriculture Organization of the United Nations indicate that if production continues to increase into 2030, aquaculture will account for nearly 60% of aquatic foods consumed by humans. This expansion isn’t limited to tonnage: humans’ attempts to domesticate marine species have done so at an exponential pace, with new marine species identified and tested for production each year. 

Franks: In recent years, calls advocating for expanding and intensifying aquaculture operations in the ocean specifically have grown. This growth, it’s argued, would feed the world, help solve hunger and malnutrition, and offer a path to transforming the global food system. The voices pushing for expansion are many and seem poised to potentially spur a wave of mariculture expansion. For example, legislation was recently introduced in the U.S. to assess the viability of and encourage offshore aquaculture. Multiple high-profile academic papers have been published articulating a vision for offshore aquaculture, identifying how it might be undertaken in the U.S. or which areas of the ocean might be suitable for farming. Investors — and, it’s worth noting, some of their environmental NGO partners — have touted mariculture as the future of sustainable investing. Given this enthusiasm for maricultural expansion and intensification, we thought it important to examine the potential harms of doing so in order to put all relevant information on the table rather than focus primarily or exclusively on its potential benefits to humans.

What are the risks of global marine farming continuing to expand as currently projected?

Sellars: There are several categories of risk. First, global marine farming poses risks to humans in addition to the much-touted potential benefits. For example, offshore aquaculture workers face significant risk of injury and other occupational hazards, including decompression sickness, electrocution, and drowning. Consumers of maricultured products may be exposed to bioaccumulated pollutants, and the widespread use of antibiotics in mariculture creates suitable conditions for the emergence of antibiotic resistance. 

In addition to these human risks, mariculture also poses a host of potential harms to ecosystems and wildlife. These harms can be understood along four different dimensions: abiotic environmental impacts, detriments to wildlife populations and the welfare of individual wild animals, captivity effects on farmed animals, and changes in how humans view the nonhuman world. For the environmental risks, we found that mariculture infrastructure and husbandry practices can pollute surrounding waters with microplastics, antibiotics, fish waste, and uneaten feed and risk driving “ocean sprawl,” the proliferation of artificial structures in the ocean. Second, for the threats to wildlife at the species-, population-, and individual-level, we found, for example, that mariculture intensifies fishing pressure, catching and using wild fishes as feed ingredients. At the individual animal level, mariculture displaces, attracts, and can entangle a variety of marine animals, like seabirds, seals and other pinnipeds, dolphins, and whales. Third, mariculture by its nature subjects animals to captivity, which has a suite of associated harms, including high rates of disease, parasitism, and deformities and inhumane slaughter. And finally, we found that mariculture threatens to alter how humans view the ocean and its inhabitants by encouraging humans to view the marine environment as an extractable resource and setting the conditions for human-wildlife conflict. So far, there hasn’t been a single, organizing principle for identifying and connecting these distinct-yet-interrelated nonhuman impacts. Our research was the first to link these harms together under a single concept, “dewilding.” 

You propose the term “dewilding” to describe marine aquaculture’s impacts on animals and their ecosystems. Why “dewilding”? Why is it important to have one term to sum up these collective impacts?

Franks: When we undertook this project, we set out to conduct a literature review to assemble the current state of knowledge of mariculture’s environmental and animal impacts. But we quickly hit a wall because there wasn’t any vocabulary available to collect all these harms under a single heading. If we had been examining terrestrial systems, we could have searched “deforestation” in the relevant databases and felt confident that many of these nonhuman impacts would be captured in our searches. We couldn’t use “deforestation” to examine changes in the ocean since it only applies to certain marine and coastal environments, e.g., mangroves. We tried to find a marine analog that applied to all ocean environments but could not find one. So we set out to find a suitable term that could be applied to marine environments — really, any environment — and that captured the full suite of mariculture’s nonhuman impacts that have already been documented. “Dewilding,” in our view, immediately registers as negative and highlights an undoing in the natural world. In the absence of a single term referring to the full spectrum of potential nonhuman harms, we could end up discussing them in isolation, viewing the harms as unconnected and disparate, not part of a single larger picture. By connecting them together under the concept of dewilding, we can generate a more comprehensive and more accurate picture of what is at stake.

You reviewed hundreds of recent scientific journal articles describing mariculture’s dewilding impacts. What did you find?

Franks: We found that dewilding across all four dimensions — environmental, wildlife, captive, and conceptual — has already been documented, with impacts on almost every taxonomic kingdom. So even in its current nascency, mariculture is already driving dewilding impacts on a wide range of beings. The vast majority of the papers in our sample documented dewilding impacts in isolation: in other words, they documented only one type of dewilding impact. Among the papers that documented more than one dewilding impact, however, we found examples of overlap between all possible dewilding impact combinations. To us, this demonstrates that work studying these impacts together is both possible and sorely needed.

Sellars: Almost two-thirds of the papers in our sample documented captive dewilding, while almost one-quarter of papers documented environmental dewilding, 15% documented wildlife dewilding, and just over 5% documented conceptual dewilding. What was especially striking about this finding was how infrequently captive and conceptual dewilding impacts are recognized as harms. During our review, we recorded whether a paper acknowledged the impact it was studying as a harm. For example, a paper studying the genome of captive Atlantic salmon in a lab to enhance farm production would inadvertently document captive dewilding, but might fail to acknowledge the captive dewilding as a potential harm to the salmon. Though papers documenting captive dewilding dominated our sample, two-thirds of these papers did not recognize the documented impact as a harm. A similar trend emerged with conceptual dewilding, too: 96% of papers documenting conceptual dewilding did not recognize this potential harm by, for example, mapping new areas of the ocean for farming without acknowledging this mapping as a conceptual shift. Papers documenting environmental and wildlife dewilding, by contrast, almost always recognized those impacts as harms or potential harms.

What further research on marine aquaculture’s role in ‘dewilding’ impacts is needed?

Franks: Much more work to understand mariculture’s full suite of dewilding impacts is needed, but intentional work studying captive and conceptual dewilding impacts are a particularly glaring gap that must be addressed. Regarding captive dewilding, humans need to begin to recognize that there are risks and harms to the animals who are being put into systems and to take those impacts seriously in deciding whether to move forward. Animals within these farming systems not only face challenging and harmful living conditions, but also experience dewilding through selective breeding and humans’ diverting their lives on an individual level away from their own sovereignty and autonomy. Instead of leading wild lives of their own choosing, they are subjected to production optimization and logic, which in turn creates and exacerbates welfare harms. We need to understand these captive dewilding impacts more thoroughly and be willing to take them into account when discussing the various possible impacts of mariculture.

Plans to farm octopuses offer an illustrative case study. Octopuses are typically solitary animals who are aggressive towards others in captivity, yet companies seeking to farm them have touted that the animals are becoming less aggressive over generations in captivity. This development is viewed positively by the industry, but viewed under the dewilding framework, this change is a loss either way: If the octopuses remain aggressive in captivity, they’re stressed and in unsuitable conditions. If they evolve to become less aggressive, they’re no longer wild creatures. 

Sellars: We also need more work examining mariculture’s conceptual dewilding impacts. We’ve seen and are paying the price for not considering these impacts on land. Viewing land as a resource for intensive human use and extraction made possible the dramatic alteration of landscapes and fueled numerous ecological crises. Wild animals like wolves are seen as pests in part because of their perceived interference with terrestrial animal agriculture, leading to decades of conflict and extermination. Farmed terrestrial animals are often viewed as units of production to be optimized rather than sentient beings with their own autonomy. Before we go down the same path in the ocean and with marine life, we can ask ourselves whether we want to risk repeating this story. 

You found that the most highly cited scientific journal articles describing marine aquaculture’s negative impacts rarely question whether the expansion and intensification of marine aquaculture should be undertaken. Why is that?  

Sellars: This is an interesting question. While we can’t get at the answer directly, we can speculate based on a few observations. In the case of papers documenting captive and conceptual dewilding, these harms were typically documented without acknowledgement from the authors that they were risks/harms. As such, part of why we don’t see mariculture expansion and intensification questioned by these authors is that the authors themselves weren’t seeing what they were documenting as a problem in the first place. For the papers documenting environmental and wildlife dewilding, it seems that the dominant view is that the harms need to be mitigated rather than avoided altogether. 

Franks: With our work, we are trying to change the conversation. Connecting the risks of dewilding into a single picture of interrelated harms provokes the necessity of at least considering a different path. We hope that introducing the concept of dewilding compels people to see that the option of not expanding can and should be part of the conversation as well.