The highest concentrations are found from 500 to 800 m depth between Norway and Bear Island, which is also regarded as the main spawning area. Peak spawning occurs in December in the main spawning area, but also in nearby areas during summer.
Fishery
Before the mid 1960s, the fishery for Greenland halibut was mainly a coastal long line fishery off the coast of eastern Finnmark and Vesterålen in Norway. In recent years, gillnets have also been used in this fishery, and landings have varied from 3000 to above 6000 tonnes. As an effect of introducing international trawlers in the fishery in the mid 1960s, the total landings increased to about 80.000 tonnes in the early 1970s. The total landings then decreased steadily to about 20.000 tonnes until the early 1980s, and remained at this level until 1991 when the catch suddenly rose to 33.000 tonnes. From 1992, total landings have varied between 9 thousand and 19.000 tonnes with the highest values in 1999, 2004 and 2005.
Regulations and by-catch
From 1992, the Greenland halibut fishery has been restricted to vessels smaller than 28 m using long-line and gillnet. This fishery is also regulated by seasonal closure. Trawl catches are limited to by-catch only. These regulations have reduced the total landings of Greenland halibut by trawlers from 20.000 to 5000–10.000 tonnes. Landings of Greenland halibut from the directed long-line and gillnet fisheries have increased in recent years to well above the level of 2500 tonnes set by the Norwegian authorities. This is attributed to the difficulties of regulating a fishery that only lasts for a few weeks.
Stock status and setting of quotas
Greenland halibut is a long-lived species which can only sustain low exploitation.
The stock has been at a low level for several years, but there are indications of an increase in recent years. During this period, mean catches have been around 13.000 tonnes. Given the state of the stock and the current paucity of information, the fishery should not be increased further until there is better information and firm evidence of a larger stock size.