Fish are the dominant vertebrates in the ocean, yet we know little of fish contribution to carbon flux at regional to global scales. Saba et al. (2021) synthesized existing information on fish carbon flux in coastal and pelagic waters. Our synthesis estimated that fish contribute an average of about 16.1 percent to total carbon flux out of the euphotic zone but with high uncertainty (standard deviation of 13 percent). Using the mean value of model-generated global carbon flux estimates, we estimated an annual average fish-specific flux of 1.5 Pg C per year, similar to rates previously determined globally for zooplankton. We attributed the high variability in fish flux estimations to significant methodological variations and observational gaps and challenges in our present knowledge. We recommended methodological standards and research to decrease uncertainty, increase our confidence in fish carbon flux estimation, and enable identification of controlling factors to account for spatial and temporal variability. This review, along with other recent research, has fostered an emerging research direction in ocean biological carbon sink and has spurred international discussions to address the effect of fishing on potential carbon sequestration, mitigation and policy considerations, and potential repercussions on socioeconomics. Better constraints on this key component of the biological pump will provide a baseline for understanding how ongoing climate change and harvest will affect the role fish play in carbon flux.

Primary Presenter: Grace Saba, Rutgers University (saba@marine.rutgers.edu)

Authors:

Grace Saba, Rutgers University  (saba@marine.rutgers.edu)

Adrian Burd, University of Georgia  (adrianb@uga.edu)

John Dunne, NOAA/OAR/Geophysical Fluid Dynamics Laboratory  (john.dunne@noaa.gov)

Santiago Hernández-León, Universidad de Las Palmas de Gran Canaria  (shernandezleon@ulpgc.es)

Angela Martin, University of Agder  (angela.martin@uia.no)

Kenneth Rose, University of Maryland Center for Environmental Science  (krose@umces.edu)

Joseph Salisbury, University of New Hampshire  (joe.salisbury@unh.edu)

Deborah Steinberg, Virginia Institute of Marine Science, William & Mary  (debbies@vims.edu)

Clive Trueman, University of Southampton  (trueman@noc.soton.ac.uk)

Rod Wilson, University of Exeter  (R.W.Wilson@exeter.ac.uk)

Stephanie Wilson, Independent Scholar  (zooprgrl@gmail.com)