Chicken and farmed salmon have remarkably similar ecological footprints

We love our chicken. We love our salmon. Thanks to the way we grow these two popular proteins, their ecological footprints are surprisingly similar.

The key is in the feed, said UC Santa Barbara marine ecologist Ben Halpern, director of UCSB’s National Center for Ecological Analysis and Synthesis and author of an article appearing in the journal Current Biology. In an effort to show ways to reduce the significant environmental pressures of global food production, he and an international team of colleagues have delved deeply into how we breed these two hugely popular animals for consumption, focusing in particular on the dynamics between countries and sea concentrated .

“Chicken are fed fish from the sea, just like salmon, and salmon are fed plant products like soy, just like chicken,” Halpern said, comparing factory-raised broilers and farmed salmonids (salmon, sea trout and char). . In addition to land crops, chickens are fed fishmeal and fish oil; while salmon, which normally eat other fish, are farmed using land-based feeds such as oil crops, soybeans and wheat. “In a way,” he remarked, “we really do have ‘Chicken of the Sea’.”

The researchers found that 95% of the cumulative ecological footprint of these two elements (greenhouse gas emissions, nutrient pollution, freshwater consumption and spatial disturbances) is concentrated in less than 5% of the planet, with 85.5% spatial overlap between the two products. mainly due to common feed components. According to the study, the overall cumulative pressure from chicken production is highest in the United States, China and Brazil.

For fish, the highest cumulative pressures are found off the coasts of Chile, Mexico and China, with some pressure on land from salmon aquaculture. In addition, the researchers found that while chicken has nine times the ecological footprint of farmed salmon, it produces 55 times more than salmon, an efficiency largely due to chickens’ very fast reproductive cycle – six to eight weeks to get there to reach slaughter weight, versus one in two years for salmon.

Within that 5% of the planet exposed to the environmental pressures of chicken and salmon production, there are differences in the environmental efficiency of farming methods. For chicken, for example, the US (world’s largest chicken producer) and Brazil (second largest) are more efficient than China (third largest). There are also geographically varying environmental pressures related to the amount of salmon produced, suggesting opportunities to improve efficiency while minimizing environmental impact.

Chicken and salmon are among the most popular sources of protein and, according to the researchers, are relatively environmentally efficient compared to other animal protein products like beef and pork. However, the scale of their production and their overlap in terms of ecological footprint raise interesting questions about the subtle links between marine and terrestrial protein production, which in turn could offer opportunities to promote sustainability. At the same time, the study underscores the importance of integrating food policies across sectors and sectors to drive food system sustainability, say the researchers.

“We were really interested in understanding how these two extremely important and dominant foods affect our planet and how they compare,” Halpern said. “I knew from previous research that I was involved that what we feed animals is a significant part of what determines their ecological footprint, but I really didn’t expect chicken and farmed salmon to be so similar. The old adage that ‘we are what we eat’ also applies to farm animals!”