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Reconciling fisheries catch and ocean productivity

journal contribution
posted on 2023-05-19, 03:05 authored by Stock, CA, John, JG, Rykaczewski, RR, Asch, RG, Cheung, WWL, Dunne, JP, Friedland, KD, Lam, VWY, Sarmiento, JL, Reginald WatsonReginald Watson
Photosynthesis fuels marine food webs, yet differences in fish catch across globally distributed marine ecosystems far exceed differences in net primary production (NPP). We consider the hypothesis that ecosystem-level variations in pelagic and benthic energy flows from phytoplankton to fish, trophic transfer efficiencies, and fishing effort can quantitatively reconcile this contrast in an energetically consistent manner. To test this hypothesis, we enlist global fish catch data that include previously neglected contributions from small-scale fisheries, a synthesis of global fishing effort, and plankton food web energy flux estimates from a prototype high-resolution global earth system model (ESM). After removing a small number of lightly fished ecosystems, stark interregional differences in fish catch per unit area can be explained (r = 0.79) with an energy-based model that (i) considers dynamic interregional differences in benthic and pelagic energy pathways connecting phytoplankton and fish, (ii) depresses trophic transfer efficiencies in the tropics and, less critically, (iii) associates elevated trophic transfer efficiencies with benthic-predominant systems. Model catch estimates are generally within a factor of 2 of values spanning two orders of magnitude. Climate change projections show that the same macroecological patterns explaining dramatic regional catch differences in the contemporary ocean amplify catch trends, producing changes that may exceed 50% in some regions by the end of the 21st century under high-emissions scenarios. Models failing to resolve these trophodynamic patterns may significantly underestimate regional fisheries catch trends and hinder adaptation to climate change.

Funding

Australian Research Council

History

Publication title

Proceedings of the National Academy of Sciences of the United States of America

Volume

114

Issue

8

Pagination

E1441-E1449

ISSN

0027-8424

Department/School

Institute for Marine and Antarctic Studies

Publisher

Natl Acad Sciences

Place of publication

2101 Constitution Ave Nw, Washington, USA, Dc, 20418

Rights statement

Copyright 2017 The Authors

Repository Status

  • Restricted

Socio-economic Objectives

Social impacts of climate change and variability

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    University Of Tasmania

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