2020 to 2022 English Waters UK and Crown Dependency 12 metre and over vessel VMS activity by time spent (hours) in c-squares

asNeeded

Vessel Monitoring System (VMS) data for 12 metre and over UK or Crown Dependency vessels was extracted from the UK Sea Fisheries Management (SFM) Structured Query Language (SQL) database dbo.SatSighting data table. Data was extracted on 03/10/2024. Before extraction processing SQL code was developed and applied to cover several of the output requirements. The ping type field was constructed based on whether the reported instant speed on the VMS position was between 1 and 6 knots; if so, it was marked ‘fishing’ type (note ~0.8% of records did not have speed information so default to ‘non-fishing’, this includes those VMS positions in harbour without speed). The time spent (hours) metric was constructed based on time between VMS positions (ping intervals). These intervals were split in two at their midpoint and then allocated to the VMS positions either side (maximum ping interval threshold set to 2 hours). For example, for a VMS report timed at 10:00hrs, with a previous report having been sent at 08:00hrs and the next report sent at 11:00hrs, the VMS report for 10:00 hrs are allocated a total of 90 minutes (60 minutes plus 30 minutes). Gear used data from reported electronic logbooks fishing activity record information held in the UK SQL ifish2 reporting database was attached to the VMS data based on a vessel and date match. Where an exact date match was not found a vessel and month match was used and then vessel and year match. If no match found on logbooks (<1% for ‘fishing’ speed records) the primary gear as listed in vessel licence information was used instead. The extracted VMS .CSV dataset was then imported into R (version 4.2.2) for data cleaning. VMSTools package (version 0.77) was used as the primary data cleaning tool which included checking for erroneous ping coordinate and duplicated pings. Removing pings within defined harbour areas or buffer zones was not implemented but this method addition is under review for implementation in an updated method. VMSTools was also used to convert latitude/longitude coordinates in 0.05 degrees c-square grid codes and aggregate and anonymize the dataset ready for work in ArcGIS. Following review of VMSTools default data layer used for removing VMS positions on land this task was instead completed in ArcGIS Pro (version 3.0.1) using Ordnance Survey’s UK coastline boundary line (publicly accessible version available here: https://osdatahub.os.uk/downloads/open/BoundaryLine) ArcGIS Pro was also used to first clip VMS positions to UK Economic Exclusive Zone boundaries (using UK Hydrographic Office maritime boundary data: https://datahub.admiralty.co.uk/portal/apps/sites/#/marine-data-portal/datasets/bf77b2ac1b654efc95dc3665c0501e23/about). An internal UK admin areas boundaries layer (based on data received from UKHO) was then used to clip data further to just those positions with English waters. Finally, a new c-square 0.05 by 0.05 resolution grid feature class was produced using the ‘Create Fishnet’ tool. The centroid of those grid square was found using ‘Feature to Point’ and ‘Add XY Coordinates’ tools. Then R and VMSTools 0.77 package was used to convert the latitude/longitude coordinates attaching the 0.05 c-square standardized codes to the XY points. The codes were added to the fishnet grid as a new field using ‘Add Join’ tool and ‘Export Features’. The VMS data was attached to this new spatial grid layer using the c-square code identifier. The data was exported as a shapefile and uploaded to this platform. Note field names have been cut to 10 characters maximum to align with shapefile requirements.