March 28, 2022 — The following is an excerpt from an article published by Sustainable Fisheries UW:
Everything you eat costs the planet something. Land for crops and livestock, inputs to grow them, and energy for everything else. Reducing humanity’s dietary footprint will be the toughest conservation challenge of the 21st century. Electricity and transportation will eventually be 100% renewable, but there is no way to replace food—it will always have costs. The challenge will be feeding Earth’s growing population while minimizing the impacts.
On this site, we have chronicled this feeding-the-world challenge over the past few years while covering the science and math of how seafood fits in to it all. Now a new paper has taken an exciting novel approach to the food/conservation dichotomy. While most research has measured environmental impact per unit of protein or calorie, Koehn et al. 2022, The role of seafood in sustainable diets out last week in IOP Science (open access), measures environmental impact against nutrition, i.e.—how impactful is a food compared to the nutrients it provides? It’s the first paper to quantify and compare environmental impacts to nutrition, a broader and more complete look vs simply calorie or protein.
Comparing the nutrition to impact ratio of various land-based foods is fairly straightforward, especially with meats—there are only a few species of livestock raised for human consumption. Seafood is different: There are hundreds of different species humans eat, all with different nutrient profiles and impacts. Koehn et al. 2022 helps determine which types of seafood can be incorporated into a low-impact diet.
Lead author Zach Koehn said, “Diversity is important when considering how we can meet nutritional needs while limiting GHG emissions. For aquatic foods, some have emissions that are as low per nutrient richness as plants, while others have emissions as high as beef.
Small pelagics (sardines & anchovies), big pelagics (tuna & billfish) and farmed seafood like carps, bivalves, and salmon were found to be lower impact than other animal-sourced food. Nearly all the seafood products studied were lower than pork, lamb, and beef except for shrimp and crustaceans like lobster and crab.
Seafood, in all its diversity, deserves a place at the table when discussing healthy diets for the planet. With more refined data on the impacts of different seafood species, policy-makers and advocacy organizations can shape policies and campaigns to shift diets away from beef, lamb, pork, and shrimp, to lower-impact proteins like poultry and most other seafoods.