1,2,4,2,1,- 1Environmental Defense Fund, New York, NY 10010, USA
- 2Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- 3School of the Earth, Ocean & Environment, University of South Carolina, Columbia, SC 29208
- 4Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904, USA
- 5Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA 93117, USA
- 6Department of Human Dimensions of Natural Resources, Colorado State University, 2545 Research Blvd, Fort Collins, CO 80526, USA
- 7Department of Environmental Science and Policy, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
- 8Marine Policy Center, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- 9MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
- 10Climate Central, Inc., Princeton, NJ 08542, USA
- 11Gund Institute for Environment, University of Vermont, Burlington, VT 05405, USA
- 12Center for Ocean Observing Leadership, Department of Marine and Coastal Sciences, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901, USA
- 13Department of Environmental Science and Policy, University of California, Davis, Davis, CA 95616, USA
- 14College of Integrative Science and Arts, Science and Mathematics Department, Polytechnic Campus, Arizona State University, Mesa, AZ 85212, USA
- 15Department of Oceans, Hopkins Marine Station, Stanford University, 120 Ocean View Blvd, Pacific Grove, CA 93950, USA
Several initiatives to conserve, restore or better manage fisheries, fishes, whales, and other marine mammals have been proposed as natural climate solutions to sequester carbon from the atmosphere or avoid new emissions. We reviewed the knowledge and uncertainties surrounding carbon fluxes and storage mediated by these organisms to evaluate their suitability to support climate mitigation interventions. Estimates of the carbon stored within fish and marine mammal biomass ranged from 0.1-1.9 Pg C for mesopelagic fishes, 0.0020-0.016 Pg C for great whales, and 0.0065-0.0113 Pg C for all marine mammals, compared to an estimated 1.5-3 Pg C stored in all ocean biota. Epipelagic fishes, mesopelagic fishes, and great whales contribute on the order of 0.03-0.2 Pg C yr-1, 1-3 Pg C yr-1, and 0.001-0.004 Pg C yr-1, respectively, to carbon export from the ocean’s surface to below the euphotic zone, compared to an estimated total marine biological export of 9-10 Pg C yr-1. The combined flux of carbon to the atmosphere from benthic trawling, biomass extraction, and fuel consumption during commercial fishing ranged from 0.05-0.25 Pg C yr-1. Substantial uncertainties were associated with nearly all fluxes and reservoirs. The contributions of whales to carbon export and the mobilization of carbon from sediments during benthic trawling were least certain, limiting the readiness of associated pathways to provide quantifiable, high-quality carbon credits. While substantial uncertainties also surrounded mesopelagic fishes, we found that even the most conservative estimates of these organisms’ contribution to ocean carbon export were large enough to justify precautionary conservation actions.
How to cite: Collins, J., Cape, M., Boenish, R., Benitez-Nelson, C., Doney, S., Fujita, R., Gaines, S., Gruby, R., Jin, D., Kim, H., Kleisner, K., Mariani, G., Moore, L., Pershing, A., Rader, D., Roman, J., Saba, G., Sanchirico, J., Saul, S., and Savoca, M.: Natural climate solutions based on fish, fisheries, and marine mammals: Current evidence and assessment of readiness, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-26, https://doi.org/10.5194/oos2025-26, 2025.
