Size class segregation of Arctic cod (<i>Boreogadus saida</i>) in a shallow High Arctic embayment

Arctic cod (Boreogadus saida (Lepechin, 1774)) vertically segregate by size class in deep waters, but such dynamics had not been explored shallow waters. Spatial distribution of was investigated Resolute Bay, Nunavut, Canada (74°41N, 94°52W) from 20 July to 5 August 2012, using a combination hydroacoustic survey and direct capture. Hydroacoustic surveys identified two high concentrations cod, with larger individuals detected on the west side, smaller east. Catch data confirmed segregation, fish sampled side bay significantly (mean = 174 mm total length (TL); 35.9 g weight (WT)) than those east 110 TL; 9.2 WT). Fish density estimated at 3.52 fish·m −2 , extrapolated full 0.52 km 2 surveyed shoal ∼1 830 400 65 711 kg (assuming mean Smaller were more abundant (9.32 ; abundance ∼11 836 or 108 894 kg; WT g). Horizontal habitat-partitioning observed between classes over small geographic area (∼8 ), most probably due partitioned resources mitigate predation risk.