Species composition and length frequency of bycatch from exploratory longlines surveys targeting Greenland halibut in East Greenland

Bycatch is a major problem in fisheries management as can lead to a high mortality of wide array of organisms. There is little documentation of the bycatch from the Greenland halibut (Reinhardtius hippoglossoides) fishery in East Greenland. This study involved the analysis of the catch composition of exploratory longline surveys targeting Greenland halibut in East Greenland in order to assess the species composition, catch rates and length composition which are likely to be caught in the commercial fishery in this area. A total of 40 species were identified to species level. The numbers of non-targeted fish caught per Greenland halibut on the continental slope were 35, 7 and 6 for depth bands of 400-799, 800-1199 and 1200-1600 m respectively, defining the Greenland halibut longline fishery as a fishery with elevated bycatch levels. The composition of the bycatch varied with depth but primarily consisted of Macrourus berglax, Centroscyllium fabricii and Antimora rostrata with M. berglax making up approximately 80 % of the bycatch at depths between 800 and 1199 m.