Primary productivity demands of global fishing fleets

Authors

  • Reg Watson,

    Corresponding author
    1. Sea Around Us Project, Fisheries Centre, University of British Columbia, Vancouver, BC, Canada
    2. Institute of Marine and Antarctic Studies, University of Tasmania, Taroona, Tasmania, Australia
    • Correspondence:

      Reg Watson

      Institute for Marine and Antarctic Studies

      University of Tasmania

      Private Bag 49

      Hobart

      TAS 7001

      Australia

      Tel.: (61) 3 6224 8574

      Fax: (61) 3 6224 8574

      E-mail: rwatson@ecomarres.com

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  • Dirk Zeller,

    1. Sea Around Us Project, Fisheries Centre, University of British Columbia, Vancouver, BC, Canada
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  • Daniel Pauly

    1. Sea Around Us Project, Fisheries Centre, University of British Columbia, Vancouver, BC, Canada
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Abstract

To be sustainable, the extractive process of fishing requires biomass renewal via primary production driven by solar energy. Primary production required (PPR) estimates how much primary production is needed to replace the biomass of fisheries landings removed from marine ecosystems. Here, we examine the historical fishing behaviour of global fishing fleets, which parts of the food web they rely on, which ecosystems they fish and how intensively. Highly mobile European and Asian fleets have moved to ever more distant productive waters since the 1970s, especially once they are faced with the costs of access agreements for exclusive economic zones (EEZs) declared by host countries. We examine fleet PPR demands in the context of large marine ecosystems (LMEs), which are frequently fished with PPR demands well above their average primary productivity (PP). In some cases, this was mitigated by subsequent emigration of fleets or by management intervention. Fleet movements, however, have stressed additional marine areas, including the EEZs of developing countries. This suggests the potential for spatial serial depletion, if fishing capacity is not reduced to more sustainable PP removal levels. Fundamentally, fishing is limited by solar-powered PP limits. Fishing beyond solar production has occurred, but in the future, marine systems may not be as forgiving, especially if overfishing and climate change compromise their resilience.

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