geosciences Article Identifying Trawl Marks in North Sea Sediments Ines Bruns 1,2,* , Peter Holler 1 , Ruggero M. Capperucci 1 , Svenja Papenmeier 3 and Alexander Bartholomä 1 1 Senckenberg am Meer, Department for Marine Research, Südstrand 40, 26382 Wilhelmshaven, Germany;
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[email protected] (A.B.) 2 Department of Geosciences, University of Bremen, Klagenfurter Straße 4, 28359 Bremen, Germany 3 Leibniz Institute for Baltic Sea Research Warnemünde, Seestraße 15, 18119 Rostock, Germany;
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[email protected] Received: 25 September 2020; Accepted: 21 October 2020; Published: 25 October 2020 Abstract: The anthropogenic impact in the German Exclusive Economic Zone (EEZ) is high due to the presence of manifold industries (e.g., wind farms, shipping, and fishery). Therefore, it is of great importance to evaluate the different impacts of such industries, in order to enable reasonable and sustainable decisions on environmental issues (e.g., nature conservation). Bottom trawling has a significant impact on benthic habitats worldwide. Fishing gear penetrates the seabed and the resulting furrows temporarily remain in the sediment known as trawl marks (TM), which can be recognized in the acoustic signal of side-scan sonars (SSS) and multibeam echo sounders (MBES). However, extensive mapping and precise descriptions of TM from commercial fisheries at far offshore fishing grounds in the German EEZ are not available. To get an insight into the spatial patterns and characteristics of TM, approximately 4800 km2 of high-resolution (1 m) SSS data from three different study sites in the German EEZ were analyzed for changes in TM density as well as for the geometry of individual TM.