Study suggests tailoring seafood diets to individual populations

Editor/Mohamed Shihab

By: Nicki Holmyard

Seafood is more nutritious than terrestrial animal protein and has a lower carbon footprint, according to a study published in September 2022 in the research journal Communications Earth and Environment.

The study, a collaboration between the RISE Research Institutes of Sweden, Dalhousie University’s School for Resource and Environmental Studies, and the Aquaculture Stewardship Council, provides suggestions for maximizing the nutritional value of seafood consumed around the globe and reducing the industry’s greenhouse gas through concentration on specific species and production methods.

“While many hurdles need to be overcome, we have the potential to reshape seafood production and consumption towards species that optimize nutrition while minimizing climate emissions. As a next step, such recommendations could be designed for specific population groups to meet their nutritional needs and emission reduction goals,” the authors said.

The report’s authors, led by researchers Friederike Ziegler and Peter Tyedmers, looked at the relative nutrient density and production-related greenhouse gas emissions (GHG) per edible weight of more than 200 wild-caught and farmed seafood species at the point of landing or harvest, and compared them with beef, chicken, and pork. Liveweight mass production data for 2015 was used.

They found that half of the seafood species analyzed perform better than land-based animal protein sources, particularly red meat, and that fishing for pelagic species resulted in the lowest GHG emissions impact, while crustaceans had the highest carbon footprint. Wild-caught pink and sockeye salmon, herring, mackerel, anchovies, and farmed bivalves were the top performers in terms of having the lowest GHG emissions per nutrient-density ratio.

Looking toward the future, as some governments around the world seek to lower their countries’ GHG emissions, they might move to a system that preferences seafood providing the highest nutritional value at the lowest emissions cost, or recommend avoiding seafood with poor nutrition-to-emissions ratios.

“From a global perspective, it may even be wise to promote the most-nutritious forms of seafood in nutrient-deficient populations and communities, even when production results in relatively higher emissions, while in populations not at risk for nutrient deficiencies, consumers could give more attention to the emissions than to nutritional content when choosing seafood products for their diets,” the authors wrote. “In fact, it is in nutrient-deficient population groups that any increase in seafood consumption would have the most positive effects for human nutrition.”

The high protein, fatty acid, vitamin, and mineral composition of seafood plays an important role in meeting human nutrition needs, and its consumption is promoted in government policies in many countries. However, the authors found that current public debate is focused on plant-based “green” diets, rather than on seafood-focused diets. The paper acknowledges the difficulty of shifting established norms in the global seafood industry and in consumption habits of the world’s population, but said there are methods available that could have an impact.

For the fishing sector, quota reallocations, redistributing harvest opportunities, improving cold storage capacity and capabilities to maximize preservation of catches, and differential resource rents could all be used to reposition the industry’s efforts. For aquaculture, changes in feed, gains in energy efficiency, and selective timing of harvests would provide the greatest benefits in improving the sector’s emissions-to-nutrition score. And consumers can be steered toward seafood with lower carbon footprints through innovation in the development, production, and marketing of value-added products, stronger dietary advice, and sponsored cultural events.

Fuel and feed were identified as the largest contributors to seafood emissions and differences in production and harvesting methods were found to make considerable differences to the climate performance of each species. The authors find that adopting fuel-efficient fishing methods, rebuilding overfished stocks, seeking more climate-friendly sources of fish feed, and growing more unfed fish and shellfish would all be beneficial in reducing future emission as a result of seafood harvesting and consumption.

Promoting seafood consumption over other animal proteins could improve global nutrition and future food security and help to address climate change, the study found.

“If human nutrition is the ultimate objective of fisheries and aquaculture, it is important that outputs are understood and evaluated on a nutritionally relevant basis, particularly given the diversity of species involved, [and] maximizing the nutritional output while minimizing environmental costs of seafood provisioning should be a guiding principle for policymaking in these areas,” the authors wrote.