Multi-year acoustic tracking reveals transient movements, recurring hotspots, and apparent seasonality in the coastal-offshore presence of Greenland sharks (Somniosus microcephalus)
Jena E. Edwards
Kevin J. Hedges
Nigel E. Hussey- 1Department of Biological Sciences, University of Windsor, Canada
- 2Arctic Aquatic Research Division, Fisheries and Oceans Canada, Canada
- 3Daniel P. Haerther Center for Conservation and Research, Shedd Aquarium, United States
- 4Department of Integrative Biology, University of Windsor, Canada
Variable movement strategies can complicate the conservation and management of mobile species. Given its extreme life history traits as a long-lived, deep-water species, the Greenland shark (Somniosus microcephalus) is vulnerable to fisheries bycatch, but little is known over its long-term movements across a spatially and seasonally variable Arctic environment. To address this knowledge gap, the movements of Greenland sharks in coastal fjords and offshore waters of Baffin Bay were examined using seven years of acoustic telemetry data. Seasonal patterns in broad-scale movements and inshore-offshore connectivity were compared among 155 sharks (101 males, 54 females [mean LT = 2.65 ± 0.48 m, range 0.93-3.5 m]) tagged in 6 discrete coastal locations spanning from Grise Fiord to Cumberland Sound (Nunavut). Sharks exhibited transient movements throughout coastal and offshore regions with some evidence of seasonally recurring hotspots revealed by repeat detections of individuals at sites over multiple years.. Shark presence in coastal fjords occurred exclusively during the coastal ice-free period (July to November), regardless of the location of tagging or detection, while presence in the offshore was recorded during the period of ice re-formation and cover (November to July). Through multiyear telemetry, it was possible to reveal repetitive patterns in broad-scale habitat use for a complex marine predator with direct relevance for understanding the seasonal distribution of mobile Arctic consumers and informing regional fisheries management.
Keywords: acoustic telemetry, Arctic marine ecosystem, movement ecology, Seasonality, distribution, Somniosus microcephalus
Received: 23 Mar 2022;
Accepted: 02 Sep 2022.
Copyright: © 2022 Edwards, Hedges, Kessel and Hussey. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Ms. Jena E. Edwards, University of Windsor, Department of Biological Sciences, Windsor, N9B 3P4, Ontario, Canada