by According to research, chickens and farmed salmon have a remarkably similar ecological footprint due to their diet.
The key is in the feed, says marine ecologist Ben Halpern, director of the University of California, Santa Barbara’s National Center for Ecological Analysis & Synthesis, and author of an article in the journal Current Biology.
In an effort to show ways to reduce the significant environmental impact of global food production, he and his colleagues have delved deeply into how we breed these two wildly popular animals for consumption, with a particular focus on the dynamics between land and sea .
“Chickens are fed fish from the sea, just like salmon, and salmon are fed plant products like soy, just like chicken,” says Halpern of 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 on land foods such as oil crops, soybeans and wheat. “In a way,” he notes, “we really do have a ‘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 of the two products, mainly due to common feed ingredients. 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 practices. 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 to each other,” says Halpern. “I knew from previous research that I was involved that what we feed to 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 “We are what we eat” also applies to farm animals!”
Source: UC Santa Barbara
