How important are specific areas for the fishery, and what effect does the fishery have on the ecosystem? To answer these questions, we use data from the Vessel Monitoring through Satellite (VMS) system.
The majority of the data are from the bottom trawler fleet. In the Netherlands, this is one of the most important fleets that fishes for bottom fish. There are approximately 250 ships that catch primarily plaice and sole. In bottom trawling, a perpendicular beam drags a net with mesh widths of 80 mm or more across the seabed.
Every day, the catch per species in the number of hours at sea are registered in the logbooks. This information is passed on to the General Inspection Service (AID). The AID also collects data about the movement of the ships on the North Sea using the VMS system. Transponders on the fishing ships send signals to a satellite. The relevant data (location, speed and direction) are sent directly to the AID. IMARES has been given permission to acquire and use this information for research purposes.
By analysing the data, we know when and where a ship was fishing. By linking this information together, we obtain a picture of the distribution of the fishery on the North Sea. In this way we can study specific areas regarding how important they are for the fishery and what effect the fishery will have on the bottom-living animals in that area.