Farming the Land Carries Higher Wildlife Costs Than Farming the Ocean

Shifting animal protein production from the ocean to land puts far more species at risk, according to an international study that challenges the assumptions behind Ottawa’s plan to phase out marine salmon farming in British Columbia.

By Fabian Dawson
SeaWestNews

A new international study finds that producing animal protein on land poses far greater risks to wildlife than producing the same amount of food in the ocean, raising fresh questions about Ottawa’s plan to phase out marine salmon farming in British Columbia.​

The study, published in Reviews in Fisheries Science & Aquaculture, examines what happens to biodiversity when marine animal protein is replaced with land-based alternatives and finds that, pound for pound, producing food on land puts far more species at risk.​

The peer-reviewed study was produced by an international team of fisheries and biodiversity scientists based in Australia, the UK, the United States, and Europe. The researchers say the difference comes down to how food is produced in each environment.​

On land, animal and crop production typically requires the permanent conversion of natural ecosystems into agricultural landscapes. Forests, grasslands, and wetlands are cleared, drained, or fragmented to create fields, feed crops, and grazing areas. That conversion, the paper notes, is the dominant driver of global biodiversity loss.​

By contrast, marine capture fisheries and marine aquaculture generally operate within existing ocean ecosystems rather than completely replacing them. Well-managed fisheries and aquaculture harvest protein from environments that remain structurally intact, without converting seabed or coastal waters into agricultural land.​

The study estimates that replacing marine fisheries protein with terrestrial livestock would require nearly five million square kilometres of additional agricultural land. Even substituting fishmeal used in aquaculture feeds with plant-based proteins such as soy would require more than 47,000 square kilometres of new cropland, expanding pressure on already stressed terrestrial ecosystems.​

“Agriculture is the dominant cause of terrestrial and freshwater extinctions,” the authors write, adding that the risk to species is about 2.6 times higher when producing animal protein on land than when producing the same amount of animal protein in the ocean.

The findings intersect directly with federal aquaculture policy in British Columbia, where Ottawa plans to remove open-net pen salmon farms from coastal waters by 2029. While federal documents describe a “transition” to alternative technologies, the policy has, in practice, steered expectations toward land-based salmon farming as the main replacement for current ocean production.​

Land-based systems, commonly referred to as recirculating aquaculture systems (RAS), raise fish in tanks on land using filtered and recycled water. While these facilities avoid direct interaction with marine ecosystems, they rely heavily on land-based inputs, including electricity, construction materials, water treatment infrastructure, and agricultural feed crops.​

A 2025 government-commissioned analysis found that land-based alternatives are nowhere near ready to support the scale of B.C.’s aquaculture production, raising red flags over food security, land availability, market stability, freshwater and energy use, and the future of Indigenous and rural livelihoods.​

The British Columbia Salmon Aquaculture Land-Based Siting and Alternative Technology Assessment details that globally, only a handful of land-based salmon farms have reached production levels exceeding 2,500 tonnes annually, and most have not demonstrated long-term profitability.​

Adding to the economic pitfalls are site limitations. The report notes that each land-based facility requires “around 4–5 hectares of flat land,” massive volumes of high-quality freshwater, and substantial electrical infrastructure.​

The report also signalled that a large-scale shift to land-based salmon farming in B.C. would not only strain the province’s power grid but also risk undermining the sector’s overall environmental performance by increasing greenhouse gas emissions, which is   contrary to the goals of the current Mark Carney-led Federal Government.​

According to the report, producing enough salmon on land to meet global demand would require as much energy as it takes to power a city of 1.2 million people and would result in significantly higher CO₂ emissions than current marine-based production scenarios.​

The latest study by the international team does not evaluate individual salmon farming technologies, but its authors caution against assuming that shifting food production from the ocean to land inherently reduces environmental risk.​

“Replacing marine with terrestrial animal protein sources may cause more biodiversity loss, not less,” the paper concludes, urging policymakers to evaluate food systems as integrated ecological networks rather than isolated sectors.​

Currently, ocean-raised salmon generate over $1.17 billion for the B.C. economy, support 4,560 well-paid full-time jobs, and remain the province’s top agri-food export.​

B.C. salmon farmers emit only 2.2 kilograms of carbon dioxide for every kilogram of edible fish produced. That is less than half of any animal raised on land, including 5.1 kilograms of CO₂ per kilogram of chicken, 6.4 kilograms for pork, and 37.2 kilograms for beef.

They are among the most climate-efficient animal protein producers in the world, helping B.C. reduce its overall greenhouse gas emissions from food production. Salmon farmers like Mowi and others have been ranked as the top animal protein producers by the Coller FAIRR Protein Producer Index – the most detailed assessment of the world’s largest meat, dairy and aquaculture companies.​

Image courtesy of Creative Salmon