The objectives are to develop improved methods for measurement and monitoring of fishing effort and to investigate the influence of gear parameters on fishing capacity. Fishing methods studied will include other trawl, beam trawl, pair trawl, Scottish seine and Danish anchor seine. The target species investigated will include cod, haddock, whiting, sole, plaice and nephrops. The area of study will be ICES subdivisions IVb and Ivc. National surveys will be carried out in Belgium, Denmark, England and Scotland of the towed gears most commonly used. Fleets will be subdivided on the basis of fishing method horsepower and gear size. One representative vessel and gear will be selected from each subgroup and full scale instrumental trials carried out measuring towing speed, geometry of different parts of the gear and gear towing resistance. This will enable calculation of parameters such as swept area, swept volume and gear horse power. Approximately 45 subgroups will be studied. Gear performance data will be collated with the catch and effort date for the different fleet subgroups as recorded in National Fisheries Departments databases. Both current and relevant historic landings data will be analyzed. National data will be pooled and a detailed statistical analysis will be made of relationships between vessel capacity parameters (horsepower, tonnage etc.) gear design parameters (power required to tow the gear, volume swept by trawl, seabed area swept by ropes etc.) and fishing power parameters (catch rate for given species and quarter of the year, average time fishing per quarter etc.).The results should contribute significantly in making more accurate assesments of fishing effort in North Sea fisheries and in identifying management measures for effectively controling effort.