Letter | Published:

Ploughing the deep sea floor

Nature volume 489, pages 286289 (13 September 2012) | Download Citation

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Abstract

Bottom trawling is a non-selective commercial fishing technique whereby heavy nets and gear are pulled along the sea floor. The direct impact of this technique on fish populations1,2 and benthic communities3,4 has received much attention, but trawling can also modify the physical properties of seafloor sediments, water–sediment chemical exchanges and sediment fluxes5,6. Most of the studies addressing the physical disturbances of trawl gear on the seabed have been undertaken in coastal and shelf environments7,8, however, where the capacity of trawling to modify the seafloor morphology coexists with high-energy natural processes driving sediment erosion, transport and deposition9. Here we show that on upper continental slopes, the reworking of the deep sea floor by trawling gradually modifies the shape of the submarine landscape over large spatial scales. We found that trawling-induced sediment displacement and removal from fishing grounds causes the morphology of the deep sea floor to become smoother over time, reducing its original complexity as shown by high-resolution seafloor relief maps. Our results suggest that in recent decades, following the industrialization of fishing fleets, bottom trawling has become an important driver of deep seascape evolution. Given the global dimension of this type of fishery, we anticipate that the morphology of the upper continental slope in many parts of the world’s oceans could be altered by intensive bottom trawling, producing comparable effects on the deep sea floor to those generated by agricultural ploughing on land.

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References

  1. 1.

    , & The effects of 118 years of industrial fishing on UK bottom trawl fisheries. Nature Commun. 1, 15 (2010)

  2. 2.

    et al. Sustainability of deep-sea fisheries. Mar. Policy 36, 307–320 (2012)

  3. 3.

    & Effects of mobile fishing gear on marine benthos. Conserv. Biol. 12, 1178–1179 (1998)

  4. 4.

    , & Reefs of the deep: the biology and geology of cold-water coral ecosystems. Science 312, 543–547 (2006)

  5. 5.

    Environmental impact of trawling on the seabed: a review. N. Z. J. Mar. Freshwat. Res. 26, 59–67 (1992)

  6. 6.

    The effect of commercial trawling on sediment resuspension and transport over the Middle Atlantic Bight continental-shelf. Cont. Shelf Res. 9, 841–865 (1989)

  7. 7.

    et al. Effects of experimental otter trawling on surficial sediment properties of a sandy-bottom ecosystem on the Grand Banks of Newfoundland. Conserv. Biol. 12, 1215–1222 (1998)

  8. 8.

    , , & Effects of commercial otter trawling on the physical environment of the southeastern Bering Sea. Cont. Shelf Res. 25, 1281–1301 (2005)

  9. 9.

    & Transport of particles across continental shelves. Rev. Geophys. 32, 85–113 (1994)

  10. 10.

    et al. in Continental-Margin Sedimentation: from Sediment Transport to Sequence Stratigraphy (eds . et al.) 339–380 (Blackwell, 2007)

  11. 11.

    & Processes that initiate turbidity currents and their influence on turbidites: a marine geology perspective. J. Sediment. Res. 79, 347–362 (2009)

  12. 12.

    , & Shaping of the continental rise by deep geostrophic contour currents. Science 152, 502–508 (1966)

  13. 13.

    , & The shaping of continental slopes by internal tides. Science 296, 724–727 (2002)

  14. 14.

    et al. Flushing submarine canyons. Nature 444, 354–357 (2006)

  15. 15.

    , , & Deep-water fisheries of the Northeast Atlantic: I. Description and current trends. J. Northwest Atlantic Fish. Sci. 31, 137–150 (2003)

  16. 16.

    , , & Fishing down the deep. Fish Fish. 7, 24–34 (2006)

  17. 17.

    & Análisis de la evolución de las capturas de gamba rosada, Aristeus antennatus (Risso, 1816), en los últimos decenios en Cataluña. Inf. Técn. Inv. Pesq. 142, 3–20 (1987)

  18. 18.

    , , , & Effect of commercial trawling on the deep sedimentation in a Mediterranean submarine canyon. Mar. Geol. 252, 150–155 (2008)

  19. 19.

    et al. Evidence of sediment gravity flows induced by trawling in the Palamós (Fonera) submarine canyon (northwestern Mediterranean). Deep-Sea Res. 53, 201–214 (2006)

  20. 20.

    et al. Suspended sediment fluxes and transport processes in the Gulf of Lions submarine canyons. The role of storms and dense water cascading. Mar. Geol. 234, 43–61 (2006)

  21. 21.

    et al. Understanding sediment dynamics of two large submarine valleys from seafloor data: Blanes and La Fonera canyons, northwestern Mediterranean Sea. Mar. Geol. 280, 20–39 (2011)

  22. 22.

    et al. A global map of human impact on marine ecosystems. Science 319, 948–952 (2008)

  23. 23.

    et al. Human activities on the deep seafloor in the North East Atlantic: an assessment of spatial extent. PLoS ONE 5, e12730 (2010)

  24. 24.

    Geology of mankind. Nature 415, 23 (2002)

  25. 25.

    , , , & Impact of natural (waves and currents) and anthropogenic (trawl) resuspension on the export of particulate matter to the open ocean: application to the Gulf of Lion (NW Mediterranean). Cont. Shelf Res. 28, 2071–2091 (2008)

  26. 26.

    , , , & The roles of habitat heterogeneity in generating and maintaining biodiversity on continental margins: an introduction. Mar. Ecol. 31, 1–5 (2010)

  27. 27.

    in Anthropogenic Geomorphology (eds , & ) 39–52 (Springer, 2010)

  28. 28.

    & Disturbance of the seabed by mobile fishing gear: a comparison with forest clear-cutting. Conserv. Biol. 12, 1180–1197 (1998)

  29. 29.

    Anthropogenic modification of the oceans. Phil. Trans. R. Soc. Lond. A 369, 887–908 (2011)

  30. 30.

    , , & Humans as major geological and geomorphological agents in the Anthropocene: the significance of artificial ground in Great Britain. Phil. Trans. R. Soc. A 369, 1056–1084 (2011)

  31. 31.

    , , , & Field calibration of optical sensors for measuring suspended sediment concentration in the western Mediterranean. Sci. Mar. 64, 427–435 (2000)

  32. 32.

    Commission Regulation (EC) No. 2244/2003 of 18 December 2003 laying down detailed provisions regarding satellite-based Vessel Monitoring Systems. Official J. Eur. Union L333, 17–27 (2003); uri = OJ:L:2003:333:0017:0027:EN:PDF.

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Acknowledgements

This work was supported by various research projects: HERMIONE (226354 and CTM2010-11084-E), DOS MARES (CTM2010-21810-C03), OASIS DEL MAR—Obra Social “la Caixa”, GRACCIE-CONSOLIDER (CSD2007-00067) and REDECO (CTM2008-04973-E). We also received support from Catalan Government Grups de Recerca Consolidats grants (2009 SGR 899 and 1305). VMS data and support were provided by the Spanish General Secretariat of Maritime Fishing (SEGEMAR). Assistance at sea by the crews of RV Hespérides, RV Sarmiento de Gamboa and RV García del Cid is also acknowledged. J.M. was funded through a JAE-DOC contract granted by Consejo Superior de Investigaciones Científicas and co-financed by the European Social Fund. F. Sardà and T. Milligan provided comments on the manuscript. The final document benefited from a review by P. Talling.

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Affiliations

  1. Marine Sciences Institute, CSIC, E-, Spain

    • Pere Puig
    • , Joan B. Company
    • , Jacobo Martín
    •  & Albert Palanques
  2. CRG Marine Geosciences, University of Barcelona, E-08028 Barcelona, Spain

    • Miquel Canals
    • , David Amblas
    • , Galderic Lastras
    •  & Antoni M. Calafat

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Contributions

All authors contributed to the design and implementation of the experimental strategy. P.P., M.C. and J.B.C. steered the integration and joint analysis of the data. P.P. and J.M. drafted the manuscript, which was critically revised and implemented by M.C. and J.B.C. M.C. designed and coordinated the acquisition of seafloor data, including multibeam bathymetry and ROV observations, and obtained VMS data. P.P., J.M. and A.P. acquired and processed the mooring time series and the sediment cores. J.M. and J.B.C. conducted the bibliographical survey of global slope fishing grounds. D.A., M.C. and P.P. produced the various maps in the paper, to which J.M and J.B.C. contributed. G.L. coordinated the multibeam bathymetry processing and, jointly with M.C., created the slope failures table. J.B.C. provided knowledge about local fishing activities. M.C., D.A., G.L. and A.M.C. described and interpreted the whole set of seafloor data. All authors discussed the results and commented on the final version of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Pere Puig.

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    Supplementary Information

    This file contains Supplementary Text, Supplementary Figures 1-5, Supplementary Table 1 and Supplementary References.

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https://doi.org/10.1038/nature11410

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