First documented large-scale horizontal movements of individual Arctic cod (Boreogadus saida)

Abstract

Arctic cod (Boreogadus saida) are a key component of the Arctic marine ecosystem. Understanding their movements and distribution is important for predicting future trends in response to climate change. It was commonly assumed that Arctic cod move horizontally throughout the Arctic, but this was so far unproven. In July 2012, 85 Arctic cod were implanted with acoustic transmitters at Resolute Bay, Nunavut, Canada. Five (5.9%) were subsequently detected ∼192 km due east along the Barrow Strait, between 67 and 215 days after last detection in Resolute Bay (mean ± SE = 161.4 ± 26.7 days). Minimum transition rates ranged between 0.89 and 2.87 km·day−1 (mean ± SE = 1.4 ± 0.4 km·day−1). A combination of factors, most notably sea ice extent, make it highly improbable that the detections were representative of predated or scavenged Arctic cod. This represents the first confirmed account of large-scale horizontal movements by this or any Arctic forage fish species. With continuing miniaturization of acoustic telemetry tags, increasing battery life, and expanded receiver coverage, it will be possible to gain a more comprehensive understanding of Arctic cod movements.