Size class segregation of arctic cod (Boreogadus saida) 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 in shallow waters. Spatial distribution of Arctic cod was investigated in Resolute Bay, Nunavut, Canada (74°41N, 94°52W) from 20 July to 5 August 2012, using a co...

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Bibliographic Details
Published in:Arctic Science
Main Authors: Kessel, S. T., Crawford, R. E., Hussey, N. E., Ivanova, S. V., Holden, J. P., Fisk, A. T.
Format: Text
Language:unknown
Published: Scholarship at UWindsor 2021
Subjects:
Conspecific predation
Habitat partitioning
Hydroacoustics
Northwest Passage
Resolute Bay
Resource competition
Arctic
Nunavut
Canada
Arctic cod
Boreogadus saida
Northwest passage
Online Access:https://scholar.uwindsor.ca/glierpub/277
https://doi.org/10.1139/as-2019-0005
Description
Summary:Arctic cod (Boreogadus saida (Lepechin, 1774)) vertically segregate by size class in deep waters, but such dynamics had not been explored in shallow waters. Spatial distribution of Arctic cod was investigated in Resolute Bay, Nunavut, Canada (74°41N, 94°52W) from 20 July to 5 August 2012, using a combination of hydroacoustic survey and direct capture. Hydroacoustic surveys identified two high concentrations of Arctic cod, with larger individuas detected on the west side, and smaller individuals on the east. Catch data confirmed size segregation, with fish sampled on the west side of the bay significantly larger (mean = 174mmtotal length (TL); 35.9 g weight (WT)) than those on the east (mean = 110mm TL; 9.2 g WT). Fish density on the west was estimated at 3.52 fish·m−2, extrapolated to the full 0.52 km2 of the surveyed shoal to ∼1 830 400 fish and 65 711 kg (assuming a 35.9 g mean WT). Smaller fish on the east side were more abundant (9.32 fish·m−2; total abundance ∼11 836 400 fish or 108 894 kg; mean WT = 9.2 g). Horizontal habitat-partitioning was observed between Arctic cod size classes over a small geographic area (∼8 km2), most probably due to partitioned resources and to mitigate predation risk.

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