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Tracking the global footprint of fisheries

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Science  23 Feb 2018:
Vol. 359, Issue 6378, pp. 904-908
DOI: 10.1126/science.aao5646
  • Fig. 1 The spatial footprint of fishing.

    (A to D) Total fishing effort [hours fished per square kilometer (h km−2)] in 2016 by all vessels with AIS systems (A), trawlers (B), drifting longliners (C), and purse seiners (D). (E) Examples of individual tracks of a trawler (blue), a longliner (red), and a purse seiner (green). Black symbols show fishing locations for these vessels, as detected by the neural network, and colored lines are AIS tracks. (F) Global patterns of average annual NPP [expressed as milligrams of carbon uptake per square meter per day (mg C m−2 day−1)] are shown for reference.

  • Fig. 2 The temporal footprint of fishing.

    Fishing hours by day and latitude (A) and seasonal patterns of marine net primary production (B). (C) Fishing hours per day for the Chinese fleet, with annual moratoria and the Chinese New Year highlighted. Light pink shading shows where some regions in the Chinese EEZ observe fishing moratoria, and dark pink shading shows where most of the Chinese EEZ is under moratorium. (D) In contrast, non-Chinese vessels show a strong weekly pattern and a drop in effort due to the Christmas holiday. Insets in (A) highlight periods of low effort around (i) annual fishing moratoria in Asian waters, (ii) Christmas in North America and Europe, and (iii) weekends, as well as (iv) a seasonal signal for longline fishing in the Southern Hemisphere (Fig. 3C).

  • Fig. 3 Effects of climatic variation on fishing effort distribution.

    (A) Sea surface temperature anomalies in 2015, with boxes outlining regions analyzed in subsequent panels. (B) In the equatorial Pacific, the average longitude of fishing effort for drifting longlines (b.2) shifts slightly eastward, correlated with an El Niño–Southern Oscillation (ENSO) event (b.3). The closure of the Phoenix Islands Protected Area (PIPA) (red arrow) had a similarly strong effect on the distribution of fishing effort and resulted in an effort gap after January 2015. The dashed lines mark the eastern and western extents of PIPA. (C) Longline fleets in the Indian Ocean fished 70 to 90 km farther south in July of 2015 than in July of 2014 or 2016, tracking water masses ranging between 16° and 19°C. White dots show the mean latitude of fleets each July.

  • Fig. 4 Response to economic forcing.

    (A) Monthly averages of the global price of marine diesel oil (gray line) and total hours at sea by the global fishing fleet after removing seasonality (solid black line) reveal that a large decrease in fuel price from 2013 to 2016 corresponded to minimal change in fishing activity (the dashed line corresponds to the trend component via additive decomposition). (B) The short-run price elasticity of fuel demand (–0.06, P < 0.001; error bar denotes 95% confidence interval) is comparable to those in other sectors.

Supplementary Materials

  • Tracking the global footprint of fisheries

    David A. Kroodsma, Juan Mayorga, Timothy Hochberg, Nathan A. Miller, Kristina Boerder, Francesco Ferretti, Alex Wilson, Bjorn Bergman, Timothy D. White, Barbara A. Block, Paul Woods, Brian Sullivan, Christopher Costello, Boris Worm

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Figs. S1 to S9
    • Tables S1 to S8
    • References

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