Possible future scenarios in the gateways to the Arctic for Subarctic and Arctic marine systems: II. prey resources, food webs, fish, and fisheries

Abstract

Climate change impacts are pronounced at high latitudes, where warming, reduced sea-ice-cover, and ocean acidification affect marine ecosystems. We review climate change impacts on two major gateways into the Arctic: the Bering and Chukchi seas in the Pacific and the Barents Sea and Fram Strait in the Atlantic. We present scenarios of how changes in the physical environment and prey resources may affect commercial fish populations and fisheries in these high-latitude systems to help managers and stakeholders think about possible futures. Predicted impacts include shifts in the spatial distribution of boreal species, a shift from larger, lipid-rich zooplankton to smaller, less nutritious prey, with detrimental effects on fishes that depend on high-lipid prey for overwinter survival, shifts from benthic- to pelagic-dominated food webs with implications for upper trophic levels, and reduced survival of commercially important shellfish in waters that are increasingly acidic. Predicted changes are expected to result in disruptions to existing fisheries, the emergence of new fisheries, new challenges for managing transboundary stocks, and possible conflicts among resource users. Some impacts may be irreversible, more severe, or occur more frequently under anthropogenic climate change than impacts associated with natural variability, posing additional management challenges.

Borealization of nearshore fishes on an interior Arctic shelf over multiple decades

“…The shift in fish communities demonstrated here is consistent with borealization because the catch rate and proportion of species spanning boreal and Arctic habitats (i.e., Arctic‐boreal distribution) increased over 30 years, while the catch rate and proportion of Arctic specialists declined. This borealization shift is novel because it did not occur on an Arctic inflow shelf and was not connected to recent climate‐driven northward range expansions across the Arctic inflow shelves (Fossheim et al, 2015; Mueter et al, 2021; Mueter & Litzow, 2008; Wassmann et al, 2011). Similar increases in boreal species with a pre‐existing presence in the Arctic and declines in endemic Arctic species have been identified for fish (Fossheim et al, 2015; Mueter & Litzow, 2008) and seabirds (Descamps & Strøm, 2021).…”

Northward Range Expansion of Subarctic Upper Trophic Level Animals into the Pacific Arctic Region

“…However, the marginal ice zone can provide a rich foraging opportunity (Hunt et al, 1996), as zooplankton and fish species often aggregate at ice edge habitats (Daase et al, 2021). Changes in sea ice extent and water temperature have resulted in changes in the available prey field for seabirds throughout the Arctic (Mallory et al, 2010;Frederiksen et al, 2013;Gall et al, 2017;Mueter et al, 2021a). For instance, in the North Atlantic, little auk wintering distribution expands and contracts with the distribution of their subarctic copepod prey, which is shifting northward (Amélineau et al, 2018).…”

“…While climate change is altering the entire Arctic, not every region in the highly heterogeneous Arctic is equally affected (e.g., Polyakov et al, 2020;Mueter et al, 2021a). In the Atlantic, there are two wide, deep, high-latitude gateways to the Arctic: Davis Strait (300-900 km wide) and Fram Strait/Barents Sea (~450 km wide).…”

First juvenile chum salmon confirms successful reproduction for Pacific salmon in the North American Arctic

“…Northward distribution shifts are becoming more common across many taxa with climate warming (Poloczanska et al 2013;Huntington et al 2020). At high latitudes, this is especially pronounced due to the recent acceleration of environmental change coupled with the northward flowing current systems that connect the Arctic to the Pacific and Atlantic oceans (Drinkwater et al 2021;Mueter et al 2021). Pacific salmon (Oncorhynchus spp.)…”