Trophic ecology of Greenland halibut (Reinhardtius hippoglossoides) on the Icelandic continental shelf and slope

The feeding habits of Greenland halibut (Reinhardtius hippoglossoides) in Icelandic waters were investigated. In total, 1595 Greenland halibut were collected during the period from May 1991 to March 1992. The main prey species were capelin (Mallotus villosus), eelpouts (Lycodes spp.), northern ambereye (Hymenodora glacialis) and northern shrimp (Pandalus borealis), comprising two-thirds of the total stomach contents by weight. Small crustaceans, mainly euphausiids, were the main prey of the smallest (<20 cm) Greenland halibut, whereas capelin and shrimps dominated the diet of fish 20–59 cm in length. The largest individuals (>80 cm) mainly consumed eelpouts and other relatively large fish. This ontogenetic shift in diet was confirmed by multivariate canonical correspondence analysis (CCA), which explained 6% of the total variation in the diet composition. The CCA further revealed spatial and seasonal effects on the variation in diet. This study indicates that small and medium-sized Greenland halibut (<60 cm) off Iceland are mainly pelagic or semi-pelagic feeders, whereas the largest individuals (>80 cm) seem to feed mainly on or near the bottom.