Study Reveals Environmental Impacts of Seafood in U.S.
Research examines the environmental footprint of aquatic foods and identifies the most sustainable choices for U.S. consumers.
Key Takeaways
- Aquatic foods vary widely in energy use, greenhouse gas emissions, and fresh water use.
- All forms of sockeye salmon, frozen Alaska pollock, and canned tuna had the lowest overall environmental impacts.
- Between 22–24% of the energy, greenhouse gas emissions, and fresh water used in aquatic food systems is lost to food waste.
Americans are the world’s fourth largest consumers and largest importers of aquatic food. New research funded by the U.S. Department of Agriculture and conducted by the Johns Hopkins Center for a Livable Future can help seafood lovers make the most environmentally sound choices when opting for this popular protein source.
The team evaluated the environmental impact of the 10 most consumed seafood products in the U.S. in terms of energy use, fresh water use, and greenhouse gas emissions. They found that sockeye salmon, frozen Alaska pollock, and canned tuna had the lowest environmental impact.
The study, which appears in Global Environmental Change, is the first to look at seafood by type instead of using an average when calculating a product’s carbon footprint. Among the ways researchers parsed the choices was separating production into two main categories, farm-raised and wild-caught, and subcategories like fresh, frozen, and canned.
“In previous studies, seafood was all lumped together into an average. It was a one-point estimate, which was an average of lots of things. But we sort of exploded that seafood category to really look at the range of options within it,” said study first author David Love, PhD, MSPH, a research professor in the Center for a Livable Future.
Another novel approach taken in the study: The team didn’t stop at the production stage. They measured impact through all stages of the seafood life cycle, from production to plate, including processing, transportation, storage, and waste.
“If you look at the carbon footprint studies that are out there, they almost always stop at what's called the farm gate, before the product is delivered to the processor,” said Love. “After that, people will say it's a wash. From there on, it's pretty much going to be the same for any product. But we didn't think that would be the case.”
Their instinct was correct. While the production stage has the largest impact, studies that stop there miss the remaining 64% of the energy, 36% of the greenhouse gases, and 21% of the fresh water used in the remainder of the supply chain, the team says. That includes transportation. Roughly 70% of U.S. aquatic foods are imported, which has a big impact on products’ carbon footprints. It also includes waste. About 23% of seafood is wasted, from fish that die before they get processed, to the food that consumers throw away uneaten. Roughly 7% of the fresh seafood at grocery stores is thrown away at the end of each week, the researchers found.
As part of their study, Love’s team visited aquaculture farms and processing plants in Vietnam, Norway, Mississippi, Alabama, and Alaska. They looked at existing literature, industry databases, and trade data, and used advanced modelling software to make their calculations. These methods allowed them to estimate the environmental footprint of 1 kilogram of edible seafood while also factoring in food loss and waste throughout the process.
This comprehensive picture is not only helpful for someone who wants to make the most sustainable seafood choice, said Love, but also when choosing among all the protein sources—beef, pork, poultry, seafood, and legumes.
“I think it's important for consumers to know where seafood falls within that. Seafood is better than beef, but it has a range that is both above and below pork and poultry. Legumes and plant-based protein have the lowest carbon footprint. This study takes that seafood category and really expands what we know about the options within it.”
The study was co-authored by Love, Mark Brown, Silvio Viglia, Frank Asche, Jillian Fry, Taryn M. Garlock, Lekelia D. Jenkins, Ly Nguyen, James Anderson, Elizabeth M. Nussbaumer, and Roni Neff.
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