The advice addresses three environmental indicators within the DCF: number 5 on the spatial extent of fishing activity where trawling gears make contact with the seabed, number 6 on the concentration of such activity, and number 7 on the area of the seabed that hasn't been affected by these gears. Assessments on these indicators were carried out for each of the ICES ecoregions where sufficient data were available. The methods were also applied to additional non-EU regions like the Norwegian Sea.
Where adequate data allowed assessment, it was found that the fishing footprint – the area where fishing occurs with seafloor-contacting gears – has either decreased or remained roughly constant over the last five years. The Greater North Sea ecoregion, which has good data coverage, has seen such a reduction in area, whilst assessment of indicator 6 points to more spatially concentrated fishing activity. The Baltic Sea ecoregion meanwhile shows a lessening in area, with the concentration remaining stable. For the Celtic Seas, both the area and concentration stayed relatively constant, although these trends don't account for all nations fishing there due to missing data. For the rest of the ecoregions, insufficient data meant conclusions couldn't be drawn.
The resulting abrasion maps, summary tables, and graphs contained within the advice were compiled based on the collation of Vessel Monitoring System (VMS) and fishing vessel logbook data from countries which submitted data to ICES. As the advice output reflects the data supplied, and with 14 countries answering the call, it means that ICES cannot be completely comprehensive in its advice. This is one of several caveats that apply to the advice.
ICES has been developing ways to describe the fishing footprint using VMS data, and this is the first time the indicators have been evaluated.
Surface abrasion pressure expressed as the swept area ratio from VMS data from 2013 in ICES Greater North Sea ecoregion. Note: caveats apply when interpreting the maps in the advice.