A landmark study has shown significant unfulfilled potential for aquaculture to become more sustainable, adding to the number of species that already place limited pressure on the environment, such as seaweed, bivalves, and certain carps.
Jessica A. Gephart, assistant professor of environmental science in the College of Arts and Sciences, is the lead author of the research, entitled “Environmental performance of blue foods.” Gephart belongs to the Blue Food Assessment, an international joint initiative bringing together over 100 scientists from more than 25 institutions.
“With demand for blue foods rising around the world, we need a better understanding of the how the environmental pressures compare across this diverse group of foods so we can ensure we are eating not just nutritiously, but also sustainably,” said Gephart.
Gephart and her co-authors produced the most standardized assessment of the environmental pressures stemming from blue food production to date, covering nearly three quarters of global production, and drawing on studies collectively reporting data from more than 1,690 fish farms and 1,000 unique fishery records worldwide.
The paper finds that seaweeds and farmed bivalves, such as mussels and oysters, generate the fewest greenhouse gas and nutrient emissions and use the least land and water. Capture fisheries also result in few nutrient emissions and use limited land and water, but greenhouse gas emissions range from relatively low, such as for sardines and cod, to relatively high for flatfish and lobsters, compared to farmed fish. The paper has published in Nature and will be featured on the cover of the journal’s upcoming issue.
Commonly eaten farmed finfish, such as salmon and carp, outperform other farmed blue foods on several environmental indicators, while most blue foods outperform chicken, which generates similar environmental pressures as tilapia.
This new set of standardized metrics can be used to benchmark the environmental impacts of blue foods to steer future production toward lower emissions and resource use.
The paper also highlighted the significant potential of many subsectors, such as carp and milkfish, to improve their environmental performance through improved farm management, reduced feed conversion ratios, and innovative technological interventions. Capture fisheries also have potential to reduce greenhouse gas emissions through improved management and optimizing gear types.
“Most aquaculture systems have not realized the levels of efficiency seen in terrestrial production systems, leaving substantial opportunities for optimization and improvements in efficiency and sustainability,” said Patrik JG Henriksson, co-author and researcher at the Stockholm Resilience Centre.
This research filled gaps in previous studies on the environmental stresses associated with food production, which often exclude blue foods, and when blue foods are included, they are typically aggregated, overlooking the vast range of species that belong to blue foods.
The study will ultimately allow businesses, certifiers, NGOs, and other interested parties, including consumers, to make more informed decisions about how to support sustainable blue foods, helping also to highlight the rich diversity and variety of the blue food sector.