The aim of this research is to identify the effort of the Icelandic fishing fleet since 1950 with focus on the cod fishing fleet in Icelandic fishing grounds. Various historical records and citizen research in Iceland provide unique information and do allow for the total reconstruction of the decked vessel fleet to individual vessels from 1950. We show how composition of the fleet changed and the fleet grew in volume (GRT) and engine power (KW) until around 2000 but has shrunk since then. The total number of vessels has been similar during this period but the composition of the fleet has changed considerably. In the 1950´s the fishing fleet was composed of 44 large, mostly steam powered, sidewinder trawlers and about 600 medium to small multipurpose vessels mostly built from timber and targeting both cod and herring. Currently the fleet is composed of almost the same number of large stern trawlers, 25 large vessels fishing pelagic species and 700 smaller vessels primarily fishing groundfish and invertebrates. The small groundfish boats are now dominated by small and powerful synthetic fibre boats. The fleet sections have therefore specialized. We also construct the nominal fishing effort in Kilowatt-days for the total fleet and focus especially on changes in the cod fishing sector. This is compared to the global trend. Along with analysis of available statistics (numbers, GRT, KW and days at sea) we systematically map changes in fishing gear, technology and management that potentially affect the fishing effort.