Abundance and distribution of Arctic cod (Boreogadus saida) and other pelagic fishes over the U.S. Continental Shelf of the Northern Bering and Chukchi Seas

The ecology of gadid fishes in the circumpolar Arctic with a special emphasis on the polar cod (Boreogadus saida)

“…In regions lacking a river plume, extreme temperatures (about -1.8°C) appeared to delay hatching until after ice breakup (April-July). This may also be the case in the northern Bering Sea and Chukchi Sea, where larvae are primarily associated with offshore marine waters (De Robertis et al 2016;Kono et al 2016).…”

Autonomous vehicle surveys indicate that flow reversals retain juvenile fishes in a highly advective high‐latitude ecosystem

“…Little is known about the distribution and movements of pelagic fish populations in the region, particularly in the Chukchi Sea. Acoustic‐trawl surveys conducted in summer 2012 and 2013 established a baseline of distributions of pelagic fishes in the U.S. northern Bering and Chukchi Seas (De Robertis et al 2017). These surveys documented large numbers of pelagic age‐0 Arctic cod, with the highest abundances in the northern Chukchi Sea where the average length was 3.5 cm and < 0.3% were greater than 6.5 cm (De Robertis et al 2017).…”

“…Acoustic‐trawl surveys conducted in summer 2012 and 2013 established a baseline of distributions of pelagic fishes in the U.S. northern Bering and Chukchi Seas (De Robertis et al 2017). These surveys documented large numbers of pelagic age‐0 Arctic cod, with the highest abundances in the northern Chukchi Sea where the average length was 3.5 cm and < 0.3% were greater than 6.5 cm (De Robertis et al 2017). However, this and other surveys in the area indicate that older Arctic cod are comparatively rare on the U.S. Chukchi shelf (Logerwell et al 2015; De Robertis et al 2017).…”

“…Similarly, walleye pollock have recently become more abundant in the northern Bering Sea (Stevenson and Lauth 2019), and this may have increased the supply of walleye pollock larvae that enter the Chukchi Sea from the south in recent years. The low densities of age‐1+ relative to age‐0 gadids found on the Chukchi shelf indicate that either overwinter survival of age‐0s retained in the area is very low, or that the Chukchi shelf serves only as a summer nursery area, after which age‐0s subsequently emigrate or are transported to other areas (De Robertis et al 2017).…”

The ecology of gadid fishes in the circumpolar Arctic with a special emphasis on the polar cod (Boreogadus saida)

“…Relatively large abundances occur in the western Beaufort Sea (Benoit et al 2008) and in the eastern and northern Barents Sea, where they have supported a modest-sized fishery of up to 50,000 t in recent decades (Hop and Gjø-saeter 2013;McBride et al 2014). More recently, large aggregations of young-of-year polar cod were observed in the northeast Chukchi Sea (De Robertis et al 2016), but their origin remains unknown. Biomass estimates in the Barents Sea region peaked at 2 million t in 2006, but have declined to less than 300,000 t in 2014 in spite of relatively conservative exploitation rates between 0 and 4 % that are believed to have little impact on stock dynamics (McBride et al 2014;Havforskningsrapporten 2015;Pavel Krivosheya, PINRO, Murmansk, pers.…”