Bottom trawl fishing footprints on the world's continental shelves

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: Amoroso, RO, Pitcher, CR, Rijnsdorp, AD, McConnaughey, RA, Parma, AM, Suuronen, P, Eigaard, OR, Bastardie, F, Hintzen, NT, Althaus, F, Baird, SJ, Black, J, Buhl-Mortensen, L, Campbell, AB, Catarino, R, Collie, J, Cowan, JH, Durholtz, D, Engstrom, N, Fairweather, TP, Fock, HO, Ford, R, Galvez, PA, Gerritsen, H, Gongora, ME, Gonzalez, JA, Hiddink, JG, Hughes, KM, Intelmann, SS, Jenkins, C, Jonsson, P, Kainge, P, Kangas, M, Kathena, JN, Kavadas, S, Leslie, RW, Lewise, SG, Lundy, M, Makin, D, Martin, J, Mazor, T, Gonzalez-Mirelis, G, Newman, SJ, Papadopoulou, N, Posen, PE, Rochester, W, Russo, T, Sala, A, Semmens, JM, Silva, C, Tsoloso, A, Vanelslander, B, Wakefield, CB, Wood, BA, Hilborn, R, Kaiser, MJ, Jennings, S
• Format: Article in Journal/Newspaper
• Language: English
• Published: Natl Acad Sciences 2018
• Subjects: Environmental Sciences; Environmental Science and Management; Environmental Impact Assessment; Bering Sea; Gulf of Alaska; New Zealand; Alaska; Aleutian Islands
• Online Access: https://doi.org/10.1073/pnas.1802379115; http://www.ncbi.nlm.nih.gov/pubmed/30297399; http://ecite.utas.edu.au/131141

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 high resolution spatial data are unavailable. If SAR was =0.1, as in 8 of 24 regions, there was > 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.