Movements and growth of monkfish Lophius piscatorius tagged at the Shetland Islands, northeastern Atlantic

Movement and growth of Lophius piscatorius were investigated around the Shetland Islands, UK, in a tagging study when a total of 1768 trawl caught fish was tagged using conventional dart tags and released on inshore fishing grounds during the autumn of 2000 and the summer of 2001. This is the first tagging study to have been undertaken on the species in UK waters and for the first time provides actual growth data for the northern monkfish stock. Monkfish of between 25 and 83 cm total length were tagged. The overall recapture rate was 4.5% and times at liberty ranged from 5 to 1078 days. Recapture positions of 35% of individuals were less than 25 km from the release positions, with some recaptures close to release positions after periods of more than 1 year. Recapture locations of some individuals indicated movements between inshore grounds. During the late autumn and winter recapture locations suggested that a general offshore migration towards the shelf edge had occurred. The largest displacement recorded was 876 km with movement being from the release location at Shetland to a fishing ground at the south east of Iceland, another recapture occurred close to Faroe. This suggests that these individuals had crossed the Faroe-Shetland Channel. This is of particular importance as it may indicate a wider mixing of stocks. Growth of recaptured fish averaged 9.4 cm year−1.