Feeding of Greenland halibut (Reinhardtius hippoglossoides) in the Canadian Beaufort Sea

Trophic patterns for Greenland Halibut are reported for the first time in the Canadian Beaufort Sea and Amundsen Gulf (n = 269). Samples were collected from 2012 to 2014 on the upper (300-500 m) and lower continental slope (750-1500 m) and were analyzed for stomach contents, stable isotopes ratios and fatty acids (FA). Stomach contents indicated that Arctic Cod, Boreogadus saida, was the main prey ingested on the upper slope (50-94% of total biomass) whereas Gelatinous Snailfish (Liparis fabricii) and Zoarcids (Lycodes spp.) dominated diets on the lower slope (17-62% of total biomass). Stable isotope mixing models and FA analyses also identified benthopelagic fishes (i.e., Liparis spp., B. saida) as key prey and highlighted large dietary overlap among years and between the two depth categories. Greenland Halibut were characterized by relatively wide δ13C and narrow δ15N ranges that suggested use of both pelagic and benthic energy sources and a piscivorous diet. Calanus-type markers such as 20:1n9 dominated the FA (>20% of total FA) andemphasized the importance of pelagic-derived material in the diet. The contribution of pelagic and benthic-derived matter in the diet suggests that Greenland Halibut play a major role in the benthic-pelagic coupling for deep water communities (up to 1500 m) in the Canadian Beaufort Sea.