Larval and adult fish assemblages along the Northwest Passage: the shallow Kitikmeot and the ice-covered Parry Channel as potential barriers to dispersal

Abstract

Climate warming and sea ice decline are expected to increase fish population movements in the circumpolar Arctic, including across the Canadian Arctic Archipelago (CAA). Knowledge gaps on present distribution, habitat uses, barriers to dispersal, and population connectivity along the Northwest Passage (NWP) limit science-based management of fish in the North American Arctic. Pelagic trawl, bottom trawl, and ichthyoplankton net collections from the US Beaufort Sea to Baffin Bay between 2005 and 2017 are used to map fish distribution along the NWP and identify potential zoogeographic barriers. In the Kitikmeot (southern CAA), the combination of shallow depths, sub-zero temperatures and slow water circulation may represent a physical barrier reducing the dispersal of marine fish between western and eastern regions. In contrast, the Parry Channel (northern CAA) may exemplify a disappearing sea ice barrier as climate warming unfolds and allow new genetic exchanges.