Beam Trawl Fishing Effort

Data provided by the Marine Institute, and may also incorporate data from other agencies and bodies.

This dataset shows the distribution of fishing effort by fishing vessels according to the gear type used. Fishing effort is defined as the time spent engaged in fishing operations or time spent at sea, this time may be multiplied by a measure of fishing capacity, e.g. engine power. In this dataset fishing effort is measured as average hours spent actively fishing per kilometre square, per year. Data from years 2014 to 2018 was used to produce this data product for the Marine Institute publication the “Atlas of Commercial Fisheries around Ireland, third edition“ (https://oar.marine.ie/handle/10793/1432).

Effort for offshore fisheries is based on the following 2 primary data types - data on vessel positioning and data on gear types used: Vessel Monitoring Systems (VMS) supplied by the Irish Naval Service provide geographical position and speed of vessel at intervals of two hours or less (Commission Regulation (EC) No. 2244/2003). The data are available for all EU vessels of 12m and larger, operating inside the Irish EEZ; outside this zone only Irish VMS data are routinely available. VMS do not record whether a vessel is fishing, steaming or inactive.

Logbooks collected by the Sea-Fisheries Protection Authority and supplied by the Department of Agriculture, Food & the Marine were the primary data source for information on landings and gear types used by Irish vessels. EU Fleet Register obtained from the EU fleet register provides information for non-Irish vessels and for Irish vessels for which the gear was not known from the logbooks. Note that if vessels use more than one gear, it is possible that the gear type assigned to them was not the one that was actually used. The fishing gear data was classified into eight main groups: demersal otter trawls; beam trawls; demersal seines; gill and trammel nets; longlines; dredges; pots and pelagic trawls.

The VMS data was analysed using the approach described by Gerritsen and Lordan (IJMS 68(1)). This approach assigns effort to each of the VMS data points. The effort of a VMS data point is defined as the time interval since the previous data point. Next the data are filtered for fishing activity using speed criteria, vessels were assumed to be actively fishing if their speed fell within a certain range (depending on the fishing gear used). The points that remain are then aggregated into a spatial grid to produce a raster dataset showing fishing effort (in hours) per kilometre square per year for each gear type group. The data is available for all countries combined and for Irish vessels only.