This dataset includes long-term, spatially detailed information on UK trawl
and seine fishing effort in the North Sea, by year and ICES rectangle. The
period covered is 1923–1980 excluding the years during and immediately after
both World Wars. Effort data (number of hours fishing) are shown separately
for each of the major historical demersal trawling and seining fleets of the
UK: sailing trawlers (pre-WWII only), steam trawlers (until the 1970s), motor
trawlers, steam seiners (pre-WWII only), and motor seiners.