Summer foraging behaviour of shallow-diving seabirds and distribution of their prey, Arctic cod (Boreogadus saida), in the Canadian Arctic

Productive areas in the Canadian Arctic seasonally provide top predators with accessible and often predictable sources of energy. Arctic cod (Boreogadus saida) aggregate in shallow bays during the summer and are exploited by seabirds and marine mammals. Information concerning how prey is presented t...

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Bibliographic Details
Published in:Polar Research
Main Authors: Jordan K. Matley, Richard E. Crawford, Terry A. Dick
Format: Article in Journal/Newspaper
Language:English
Published: Norwegian Polar Institute 2012
Subjects:
Satellite schools
schooling
predators
northern fulmar
black-legged kittiwake
glaucous gull
Environmental sciences
GE1-350
Oceanography
GC1-1581
Arctic
Nunavut
Fulmar
Allen Bay
Arctic cod
Black-legged Kittiwake
Boreogadus saida
Fulmarus glacialis
Glaucous Gull
Larus hyperboreus
Northern Fulmar
Polar Research
rissa tridactyla
Online Access:https://doi.org/10.3402/polar.v31i0.15894
https://doaj.org/article/65f9eacc86414af3bd7e6e77f057c046
Description
Summary:Productive areas in the Canadian Arctic seasonally provide top predators with accessible and often predictable sources of energy. Arctic cod (Boreogadus saida) aggregate in shallow bays during the summer and are exploited by seabirds and marine mammals. Information concerning how prey is presented to predatory seabirds, and the cues seabirds use to optimize foraging potential, is limited. Hydroacoustic surveys were completed in Allen Bay, Nunavut, to determine the presence, density, abundance, and depth of Arctic cod schools in relation to shallow-diving seabirds. Schools were also documented using standardized protocols to examine the influence of environmental variables, such as wind, ice, tidal states and seabird behaviour. The presence of schools was a significant predictor of the distribution of northern fulmars (Fulmarus glacialis) but not black-legged kittiwakes (Rissa tridactyla). Glaucous gulls (Larus hyperboreus) associated with northern fulmars are likely optimizing chances of stealing Arctic cod. The density, size and depth of schools did not significantly affect the distribution of the seabirds. We speculate that Arctic cod from demersal schools separate to feed at the surface in satellite schools (groups of dispersed fish), thus reducing competition but increasing the risk of predation.

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