Publication history: Accepted - 23 August 2018; Published online - 8 October 2018.Bottom trawlers land around 19 million tons of fish and invertebrates
annually, almost one-quarter of wild marine landings. The extent of
bottom trawling footprint (seabed area trawled at least once in a
specified region and time period) is often contested but poorly
described. We quantify footprints using high-resolution satellite vessel
monitoring system (VMS) and logbook data on 24 continental shelves
and slopes to 1,000-m depth over at least 2 years. Trawling footprint
varied markedly among regions: from <10% of seabed area in Australian
and New Zealand waters, the Aleutian Islands, East Bering Sea,
South Chile, and Gulf of Alaska to >50% in some European seas.
Overall, 14% of the 7.8 million-km2 study area was trawled, and
86% was not trawled. Trawling activity was aggregated; the most
intensively trawled areas accounting for 90% of activity comprised
77% of footprint on average. Regional swept area ratio (SAR; ratio
of total swept area trawled annually to total area of region, a metric
of trawling intensity) and footprint area were related, providing an
approach to estimate regional trawling footprints when highresolution
spatial data are unavailable. If SAR was ≤0.1, as in 8 of
24 regions, therewas >95% probability that >90%of seabed was not
trawled. If SAR was 7.9, equal to the highest SAR recorded, there
was >95% probability that >70% of seabed was trawled. Footprints
were smaller and SAR was ≤0.25 in regions where fishing rates consistently
met international sustainability benchmarks for fish stocks,
implying collateral environmental benefits from sustainable fishing.Funding for meetings of the study group and salary
support for R.O.A. were provided by the following: David and Lucile Packard
Foundation; the Walton Family Foundation; the Alaska Seafood Cooperative;
American Seafoods Group US; Blumar Seafoods Denmark; Clearwater Seafoods
Inc.; Espersen Group; Glacier Fish Company LLC US; Gortons Seafood; Independent
Fisheries Limited N.Z.; Nippon Suisan (USA), Inc.; Pesca Chile S.A.;
Pacific Andes International Holdings, Ltd.; San Arawa, S.A.; Sanford Ltd. N.Z.;
Sealord Group Ltd. N.Z.; South African Trawling Association; Trident Seafoods;
and the Food and Agriculture Organisation of the United Nations. Additional
funding to individual authors was provided by European Union Project
BENTHIS EU-FP7 312088 (to A.D.R., O.R.E., F.B., N.T.H., L.B.-M., R.C., H.O.F.,
H.G., J.G.H., P.J., S.K., M.L., G.G.-M., N.P., P.E.P., T.R., A.S., B.V., and M.J.K.); the
Instituto Português do Mar e da Atmosfera, Portugal (C.S.); the International
Council for the Exploration of the Sea Science Fund (R.O.A. and K.M.H.); the
Commonwealth Scientific and Industrial Research Organisation (C.R.P. and
T.M.); the National Oceanic and Atmospheric Administration (R.A.M.); New
Zealand Ministry for Primary Industries Projects BEN2012/01 and DAE2010/
04D (to S.J.B. and R.F.); the Institute for Marine and Antarctic Studies, University
of Tasmania and the Department of Primary Industries, Parks, Water and
Environment, Tasmania, Australia (J.M.S.); and UK Department of Environment,
Food and Rural Affairs Project MF1225 (to S.J.)