A major nursery area around the Svalbard archipelago provides recruits for the stocks in both Greenland halibut management areas in the Northeast Atlantic

Greenlandhalibut in theNortheastAtlantic currently have two separatemanagementunits: theNortheastArctic (NEA) stockand theWestNordic (WN) stock. The biological basis for this separation is weak, and while the NEA stockhas a well-described nursery area in the waters around the Svalbard archipelago, no such major nursery area is known for theWN stock. To examine the linkages between these two stocks, a tagging experimentwasconducted in theSvalbardnurseryarea,which is theonly known largenurseryarea forGreenlandhalibut in theNortheastAtlantic. A total of 25 149 juvenileGreenlandhalibutwere taggedand released in theperiod2005–2008, andasof January 2014, therewere 155 recaptures: 92%were caughtmore than 170 km from the tagging site, while 59% had travelledmore than 1500 km. During the first 2 years after tagging, recaptures were reported only from the fishing grounds in the NEAmanagement area. Subsequently, the number of recaptures decreased in theNEAmanagement area, while recaptures were beginning to be reported from the WN management area, which by 2014 accounted for 61% of the total number of reported recaptures. Itwas concluded that the stocksin the twomanagement areas forGreenlandhalibut in theNortheastAtlantic have acommon nursery ground, and that a recruitment index based on data from the nursery around Svalbard would reflect possible recruitment to the stocksof both management units. The lack of recaptures on the Southeast Greenland shelf suggests a stockboundary west of Iceland. It is suggested to further explore the stockdelineation in these areas and that future stock assessmentsshould explore the potential advantage of using a combined assessment model for the two current management units.