The First Assessment of the Habitat Associations and Ecosystem Roles of Offshore Marine Fishes in the Canadian Beaufort Sea

Marine fishes play a critical role in transferring energy from lower (e.g., zooplankton, benthos) to upper (e.g., beluga whales) trophic levels in Arctic marine ecosystems. Knowledge of marine fish diversity, abundances, and habitat associations is essential to management and conservation initiatives, and is the foundation from which to study their roles in ecosystem structure and function. However, the community structure and habitat requirements of Arctic offshore marine fishes are not well known. Fisheries and Oceans Canada led the first-ever regional survey of offshore marine fishes and habitats in the Canadian Beaufort during 2012-2014. Trawling was conducted at stations 20-1500m deep with concurrent sampling of oceanography and sediment composition. Fish community structure was assessed to determine the presence of species assemblages, and habitat parameters were assessed as explanatory variables for community structure. Using stable isotopes and fatty acids, the ecological role of Greenland Halibut (Reinhardtius hippoglossoides) was examined in the context of predator-prey interactions across benthic and pelagic habitats to demonstrate the importance of understanding habitat associations of both predators and prey to manage fisheries resources in an ecosystem context. Increased knowledge of key fish species and their habitat associations provides a basis for oceans management and fisheries assessment and protection.