Migration from Nursery to Spawning Area in relation to growth and maturation of Greenland Halibut (Reinhardtius hippoglossoides) in the Northeast Arctic

Summary

The population structure of the concentrations of Greenland halibut (Reinhardtius hippoglossoides (Wabaum, 1792)) in relation to distribution area and state of maturity is described based on 12 trawl surveys conducted in the spawning, nursery and feeding areas along the Norwegian Continental Slope between October 1996 and January 1999. Based on these, inferences are made of how the migration from nursery to spawning area depends on individual characteristics, such as sex, maturity stage and previous growth history, and how emigration from nursery is linked to immigration to the spawning area. Descriptions are also given of the age and length structure of the different maturity groups in the spawning area. It was inferred that for both males and females, the fast growing individuals left the nursery first, and there was no obvious sex-difference in emigration rate from the nursery area. The early maturing females that are found along with those close to spawning have low growth rates and are thus not representative of all the next year's spawners, as previously suggested. Before spawning stock biomass can be realistically modelled, similar studies should also be made on the vertical component of migration and all the migration processes should be quantified.