Study finds seafood's 'blue' diet potential

Sustainable seafood can provide more nutrition for humans than beef, pork and chicken while reducing greenhouse gas emissions, according to a paper published recently in the journal Communications-Earth and Environment. These findings suggest that policies to promote seafood diets as an alternative to other animal proteins may improve future food security and help combat climate change.

To meet population size growth, the global human diet needs to be more nutritious while reducing its climate footprint. Seafood is known to be a good source of protein, fatty acids, vitamins and minerals, and previous studies have shown the potential environmental benefits of replacing meat with seafood in the diet. However, future dietary strategies that seek to reduce climate emissions often promote a plant-based "green" diet, ignoring the potential of a seafood-based "blue" diet.

Peter Tyedmers, Dalhousie University, Halifax, Canada, Elinor Hallstrom, Swedish Research Institute, Gothenburg, Sweden, and team analyzed the nutrient density and climate impacts of globally important wild-caught and farmed sources of seafood from a wide range of fisheries and aquaculture sources in 2015.

The team found that wild-caught salmon, herring, mackerel and anchovy, as well as farmed mussels and oysters, had the lowest climate impacts for the same nutritional value. Half of the seafood analyzed was more nutrient dense than beef, pork and chicken, and had lower greenhouse gas emissions. Differences in production and capture methods can make a big difference in the climate impact of each species. The team recommends that to further reduce emissions, fisheries should adopt energy-efficient fishing techniques and rebuild depleted stocks, while raising more unconsumed fish and shellfish and identifying more climate-friendly sources of fish feed.

The study focused on greenhouse gas emissions rather than potential impacts on ecosystems, but the findings still highlight the potential for seafood to provide a sustainable and nutrient-rich food source that is beneficial to the climate. The researchers argue that policies to help combat climate change and poor diets should promote sustainable seafood consumption.