Estimating seabed pressure from demersal trawls, seines, and dredges based on gear design and dimensions

Type Article
Date 2016-01
Language English
Author(s) Eigaard Ole R.1, Bastardie Francois1, Breen Mike2, Dinesen Grete E.1, Hintzen Niels T.3, Laffargue PascalORCID4, Mortensen Lars O.1, Nielsen J. Rasmus1, Nilsson Hans C.5, O'Neill Finbarr G.6, Polet Hans7, Reid David G.8, Sala Antonello9, Skold Mattias5, Smith Chris10, Sorensen Thomas K.1, Tully Oliver8, Zengin Mustafa11, Rijnsdorp Adriaan D.3
Affiliation(s) 1 : Tech Univ Denmark, Natl Inst Aquat Resources, DK-2920 Charlottenlund, Denmark.
2 : Inst Marine Res, POB 1870, N-5817 Bergen, Norway.
3 : IMARES, POB 68, NL-1970 AB Ijmuiden, Netherlands.
4 : IFREMER, Nantes, France.
5 : Swedish Univ Agr Sci, Dept Aquat Resources, Inst Marine Res, Turistgatan 5, S-45330 Lysekil, Sweden.
6 : Marine Scotland Sci, 375 Victoria Rd, Aberdeen AB11 9DB, Scotland.
7 : Inst Agr & Fisheries Res, Animal Sci Unit, Fisheries & Aquat Prod, Ankerstr 1, B-8400 Oostende, Belgium.
8 : Marine Inst, Oranmore, Co Galway, Ireland.
9 : Inst Marine Sci CNR ISMAR, Natl Res Council, Ancona, Italy.
10 : Hellen Ctr Marine Res, Iraklion, NE, Greece.
11 : Cent Fisheries Res Inst, TR-61100 Trabzon, Turkey.
Source Ices Journal Of Marine Science (1054-3139) (Oxford Univ Press), 2016-01 , Vol. 73 , N. suppl.1 , P. i27-i43
DOI 10.1093/icesjms/fsv099
WOS© Times Cited 144
Note Contribution to the Supplement: ‘Effects of Fishing on Benthic Fauna, Habitat and Ecosystem Function’
Keyword(s) benthic impact, fishing pressure, gear footprint, indicators, logbooks, seabed integrity, swept-area, towed gears, vessel size
Abstract This study assesses the seabed pressure of towed fishing gears and models the physical impact (area and depth of seabed penetration) from trip-based information of vessel size, gear type, and catch. Traditionally fishing pressures are calculated top-down by making use of large-scale statistics such as logbook data. Here, we take a different approach starting from the gear itself (design and dimensions) to estimate the physical interactions with the seabed at the level of the individual fishing operation. We defined 14 distinct towed gear groups in European waters (eight otter trawl groups, three beam trawl groups, two demersal seine groups, and one dredge group), for which we established gear “footprints”. The footprint of a gear is defined as the relative contribution from individual larger gear components, such as trawl doors, sweeps, and groundgear, to the total area and severity of the gear's impact. An industry-based survey covering 13 countries provided the basis for estimating the relative impact-area contributions from individual gear components, whereas sediment penetration was estimated based on a literature review. For each gear group, a vessel size–gear size relationship was estimated to enable the prediction of gear footprint area and sediment penetration from vessel size. Application of these relationships with average vessel sizes and towing speeds provided hourly swept-area estimates by métier. Scottish seining has the largest overall gear footprint of ∼1.6 km2 h−1 of which 0.08 km2 has an impact at the subsurface level (sediment penetration ≥ 2 cm). Beam trawling for flatfish ranks low when comparing overall footprint size/hour but ranks substantially higher when comparing only impact at the subsurface level (0.19 km2h−1). These results have substantial implications for the definition, estimation, and monitoring of fishing pressure indicators, which are discussed in the context of an ecosystem approach to fisheries management.
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Eigaard Ole R., Bastardie Francois, Breen Mike, Dinesen Grete E., Hintzen Niels T., Laffargue Pascal, Mortensen Lars O., Nielsen J. Rasmus, Nilsson Hans C., O'Neill Finbarr G., Polet Hans, Reid David G., Sala Antonello, Skold Mattias, Smith Chris, Sorensen Thomas K., Tully Oliver, Zengin Mustafa, Rijnsdorp Adriaan D. (2016). Estimating seabed pressure from demersal trawls, seines, and dredges based on gear design and dimensions. Ices Journal Of Marine Science, 73(suppl.1), i27-i43. Publisher's official version : https://doi.org/10.1093/icesjms/fsv099 , Open Access version : https://archimer.ifremer.fr/doc/00310/42137/