Advancing research for the management of long-lived species: A case study on the Greenland shark (2019)

Jena E. Edwards1*, Elizabeth Hiltz2, Franziska Broell1, Peter G. Bushnell3, Steven E. Campana4, Jørgen S. Christiansen5,6, Brynn M. Devine7, Jeffrey J. Gallant8, Kevin J. Hedges9, M. Aaron MacNeil10, Bailey C. McMeans11, Julius Nielsen12, Kim Præbel13, Gregory B. Skomal14, John F. Steffensen15, Ryan P. Walter16, Yuuki Y. Watanabe17, David L. VanderZwaag18 and Nigel E. Hussey1
COVER IMAGES: (1) Baie-Saint-Pancrace near Baie-Comeau, Québec. Nowhere in the world have there been more encounters between Greenland sharks and scuba divers. This was one of the locations in our two telemetry studies that are discussed in the following research paper. (2) Looking for Greenland sharks near Baie-Comeau, Québec. (3) Greenland shark in Baie-Saint-Pancrace. Photos © Jeffrey Gallant | GEERG
1Department of Biological Sciences, University of Windsor, Windsor, ON, Canada
2Fisheries Management, Fisheries and Oceans Canada, Winnipeg, MB, Canada
3Department of Biological Sciences, Indiana University South Bend, South Bend, IN, United States
4Faculty of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland
5Faculty of Biosciences, Fisheries and Economics (BFE), Department of Arctic and Marine Biology (AMB), UiT The Arctic University of Norway, Tromsø, Norway
6Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
7Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute of Memorial University of Newfoundland, St. John’s, NL, Canada
8Greenland Shark and Elasmobranch Education and Research Group, Drummondville, QC, Canada
9Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, MB, Canada
10Department of Biology, Ocean Frontier Institute, Dalhousie University, Halifax, NS, Canada
11Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
12Greenland Institute of Natural Resources, Nuuk, Greenland
13Norwegian College of Fishery Science, UiT The Arctic University of Norway, Tromsø, Norway
14Massachusetts Division of Marine Fisheries, New Bedford, MA, United States
15Department of Biology, University of Copenhagen, Copenhagen, Denmark
16Department of Biological Sciences, California State University, Fullerton, Fullerton, CA, United States
17National Institute of Polar Research, Tachikawa, Japan
18Marine & Environmental Law Institute, Dalhousie University, Halifax, NS, Canada

Long-lived species share life history traits such as slow growth, late maturity, and low fecundity, which lead to slow recovery rates and increase a population’s vulnerability to disturbance. The Greenland shark (Somniosus microcephalus) has recently been recognized as the world’s longest-lived vertebrate, but many questions regarding its biology, physiology, and ecology remain unanswered. Here we review how current and future research will fill knowledge gaps about the Greenland shark and provide an overall framework to guide research and management priorities for this species. Key advances include the potential for specialised ageing techniques and demographic studies to shed light on the distribution and age-class structure of Greenland shark populations. Advances in population genetics and genomics will reveal key factors contributing to the Greenland shark’s extreme longevity, range and population size, and susceptibility to environmental change. New tagging technologies and improvements in experimental and analytical design will allow detailed monitoring of movement behaviours and interactions among Greenland sharks and other marine species, while shedding light on habitat use and susceptibility to fisheries interactions. Interdisciplinary approaches, such as the combined use of stable isotope analysis and high-tech data-logging devices (i.e. accelerometers and acoustic hydrophones) have the potential to improve knowledge of feeding strategies, predatory capabilities, and the trophic role of Greenland sharks. Measures of physiology, including estimation of metabolic rate, as well as heart rate and function, will advance our understanding of the causes and consequences of long lifespans. Determining the extent and effects of current threats (as well as potential mitigation measures) will assist the development of policies, recommendations, and actions relevant for the management of this potentially vulnerable species. Through an interdisciplinary lens, we propose innovative approaches to direct the future study of Greenland sharks and promote the consideration of longevity as an important factor in research on aquatic and terrestrial predators.

Keywords: Future Directions, Longevity, Management, Somniosus microcephalus, Arctic ecosystem
Received: 14 Aug 2018; Accepted: 14 Feb 2019.

Jeffrey Gallant, M.Sc., is the Scientific Director of the St. Lawrence Shark Observatory (ORS) and of the Greenland Shark and Elasmobranch Education and Research Group (GEERG). He is also the author of the Diving Almanac and a contributing editor of DIVER Magazine. Jeffrey dove with his first shark, a spiny dogfish, off Halifax (Nova Scotia) in 1991.