Abstract

On the North Sea bottom lie numerous pipelines to link oil- or gas offshore units, - platforms and processing stations on land. Although pipeline tubes are coated and covered with protective layers (Concrete Weight Coating), the pipelines risk being damaged through man-made threats like fishing activities with bottom trawls (trawling interference), anchoring and dropped objects. IRM Systems performs integrated risk assessments of pipelines for amongst others Wintershall. Spatial maps of fishing activity would contribute to this risk assessment. Therefore, WMR was tasked to quantify the amount of fishing activity in the vicinity of Wintershall pipelines. Fishing activity has been quantified at a spatial scale of approximate 2500 m2 blocks (50m by 50m) using fishing Vessel Monitoring System (VMS) data for 2016 and 2018. In total, for each year 69 shapefiles specifying the fishing intensity in a buffer area of 100m either side of the pipeline, were delivered. The overall total trawl fishing intensity in 2016 and 2018 along the pipeline trajectories ranges from 0 - 18.83 times per grid cell per year and is the result of combining all beam-trawl fleet activities, though split by large beam trawls and shrimp trawls. There is substantial difference in effort between 2016 and 2018 which varies up to 200% for some pipeline segments. Though, at the North Sea scale, fishing has been relatively stable over the past 10 years. Highest fishing intensities are recorded within the 12nm zone where the effort of the shrimp trawlers is most abundant and has increased almost 5-fold in some areas from 2010 and has not come to a halt yet. At the spatial scale relevant in this study, small spatial differences make for substantial differences though.