Spatial, seasonal and ontogenetic variation in diet of Northeast Arctic Greenland halibut (Reinhardtius hippoglossoides )

Abstract

This paper describes spatial, temporal and biotic patterns in the diet of Greenland halibut ( Reinhardtius hippoglossoides , Walbaum) sampled from three different areas of the Barents Sea, namely the Hopen Deep (nursery area), the Bear Island Channel and the continental slope (spawning ground), during April 1996 to January 1998. Percentage of empty stomachs was based on 3294 specimens, and the relative importance of prey groups was assessed using stomach contents from 486 specimens. Multivariate analyses (i.e. Correspondence Analysis and Canonical Correspondence Analysis) were applied to examine which variables could best account for dietary variation. Spatial (horizontal and vertical) and temporal components appeared to be most influential on the variation in diet composition, whereas biotic variables (i.e. predator size, sex and maturity stage) appeared to be of less importance. It is proposed that regional and seasonal differences in diet composition are caused by spatial and temporal variations in abundance and distribution of some of the major prey species, i.e. Atlantic herring ( Clupea harengus ) and capelin ( Mallotus villosus ). On the slope there were also clear ontogenetic changes in diet; in smaller Greenland halibut (<50 cm) crustaceans and the cephalopod Gonatus fabricii were the prevailing prey, whereas for larger specimens teleosts and fish offal were the dominating components of the diet. Smaller Greenland halibut appeared to have been foraging at greater depths (>700 m) than the larger ones.