Greenland sharks: old and cold

  • Sharks
Years funded
  • 2011, 2012, 2013, 2014, 2015, 2016
  • Archived
Project type
  • Research

A remarkable creature lives beneath the ice floes of the Arctic. Greenland sharks swim excruciatingly slowly, have been known to eat polar bears and live for an implausibly long time. Peter is bringing their mysteries to the surface.

Greenland sharks: old and cold

Peter Bushnell

Project leader
About the project leader
Living things are cool. As an academic with a PhD in medical physiology who spends most of his time teaching anatomy and physiology to future health professionals, I am constantly reminded of this fact. Living things in water are even cooler. As a researcher with an MSc in marine biology and a long career spent exploring how aquatic organisms function in the marine environment, I am constantly amazed and excited by every new discovery, however mundane. Over the course of my career I have been trying to combine the two fields by focusing on the application of physiology in the...
Related Blogs
By Peter Bushnell, 18th February 2015
Recovered PSAT
By Julius Nielsen and Peter Bushnell During the Greenland Shark Expedition in 2012, several Greenland sharks were tagged in the Ammasalik Fjord in south-eastern Greenland as part of a study on the migratory behaviour of the species. The tags used were pop-up satellite archival tags…
By Peter Bushnell, 11th June 2014
Greenland Shark Expedition in Disko Bay (Greenland) May 2014
Written by Julius Nielsen, Peter Bushnell Why study the Greenland shark? The Greenland shark Somniosus microcephalus is one of the world’s largest carnivorous sharks, reaching at least 5.5 metres; only the great white shark is bigger. Besides being quite large, the Greenland shark is unusual in…
By Peter Bushnell, 19th September 2012
Very old and very cold!
Greenland sharks; large, old, and incredibly slow moving. Peter Bushnell, project leader for the Save Our Seas Supported project on the Conserv ation and History of the Greenland shark, cannot really blame them. He reports from the fjords of Eastern Greenland, where the water is…
By Peter Bushnell, 30th January 2012
Sharks and the buddy system
In addition to the electropositive metal study we also deployed four pop-up satellite tags in western Greenland near Qeqertarsuaq (Disko Island, ~69º13 N, 53º.36 W) to study the Greenland shark’s short term movements. The tags reported in late 2011. Over the course of 3.5 months,…
By Peter Bushnell, 11th December 2011
Electropositive metal doesn’t scare hungry Greenland sharks
In Greenland, the longline fishery targeting halibut (Reinhardtius hippoglossoides) is plagued by a substantial bycatch of Greenland sharks (Somniosus microcephalus). This has led to a bounty for shark hearts as proof of their elimination. We went to Greenland in May to test if electropositive (EP)…
Project details

Greenland Sharks

Key objective

The general aim of this project is to deploy satellite tags on Greenland sharks and collect tissue samples for the purpose of age determination in order to better understand the species’ movements and the age structure of its population(s).

Why is this important

Fishing pressure and a lack of basic knowledge of the species’ natural history are threats to the future of the Greenland shark Somniosus microcephalus – thought by some to be the longest-lived vertebrate on earth. Effective conservation and management of any fish species requires a thorough understanding of growth rates, age at first reproduction, fecundity, distribution, population structure, etc.


Depth and location alter the amount of radioactive carbon incorporated into bodily tissues, which in turn impacts the accuracy of age estimates based on radiocarbon dating. Our two proposed projects are therefore directly related to one and other in that the water masses occupied by an animal and determinations of its age are linked. This research will address both these issues by deploying pop-up satellite archival tags (PSATs) on sharks in eastern and western Greenland, and by collecting tissue samples for radiocarbon analysis. In other research, we have already successfully deployed PSATs on Greenland sharks in north-western Greenland and had them remain attached for the full programmed period of 3.5 months. PSATs deployed in both areas will be programmed to release after one to three and nine to 12 months to provide insights into the water masses the sharks move through. These data will be important for our ageing studies, which comprise the second portion of the study. Eye lenses will be collected from sharks of various sizes for age determination using radiocarbon dating. Several fishermen and fisheries biologists are willing to assist us and supplement our efforts.

Aims & objectives

The general aim of this project is the deployment of satellite tags and collection of tissues from Greenland sharks for age determination in order to better understand their movements and the age structure of their population(s). Detailed objectives are to:

  • Deploy long-lines in north-eastern Greenland to catch (and release) Greenland sharks.
  • Record total length, girth, weight, gender, date and location of capture sharks, and release them after tagging with dart tags from the Greenland Fisheries Department.
  • Deploy eight PSATs on sharks caught by long-line that are set to release at intervals from one to 12 months.
  • Collect vertebrae and eye lenses from any dead or terminally injured sharks for ageing studies.
  • Determine age of shark tissue samples by bomb radiocarbon analysis (in collaboration with AMS 14C Dating Center, University of Aarhus, Denmark).