Abstract
Greenland halibut (Reinhardtius hippoglossoides (Walbaum)) are widely distributed over extensive geographic areas of both the Northwest and Northeast Atlantic Ocean with no break in the continuity of the respective distributions. Although the entire Greenland halibut resource in the North Atlantic is genetically homogeneous they mainly comprise a single interbreeding stock in each of the two regional areas investigated. Both stocks show similar distribution patterns over depth. Generally, larger fish become more abundant and smaller fish less abundant in progressively deeper water with peak abundance occurring over a depth range of 400-1000 m. Greenland halibut in the Northwest Atlantic were observed to be most abundant in bottom temperatures mainly between 2 °C and 6 °C compared to 0 °C to 4 °C in the Northeast Atlantic.
The fishery for Greenland halibut in the Northeast Atlantic was unregulated until 1992 although since 1995 catches substantially exceed those advised. The spawning stock size reached historically low levels during the 1990s and recruitment to the spawning stock remains uncertain based on the most recent assessment. In the Northwest Atlantic the Greenland halibut resource has been regulated by catch quota since 1974 although it was subjected to high-uncontrolled fishing pressure during the early 1990s. The spawning stock also reached historic low levels during this period but has recently showed improvement due to low fishing mortality since 1995 and better than average recruitment since 1990.
