Grey Seal Tagging in Cape Cod: A Successful Scientific Collaboration!

The northwest Atlantic grey seal population has increased markedly over the last four decades. Fisheries and Oceans Canada (DFO) has conducted considerable research in the Maritimes and Quebec on abundance, diet, and movements of this population. These activities have provided new insights into grey seal ecology, as well as crucial information related to grey seal–fisheries interactions.

South of the border, grey seal numbers have also been increasing and, in recent years, there have been concerns about grey seal impacts on commercial fisheries, fisheries' impacts on seals (bycatch), seals attracting sharks to coastal areas, and E. coli counts around grey seal haul-out sites.

American researchers have had less exposure to handling grey seals. To assist with the sedation and handling of grey seals in nets, NOAA’s Northeast Fisheries Science Center, Massachusetts, invited us (Mike Hammill and Jean-François Gosselin, from Maurice Lamontagne Institute) to participate in fieldwork in Chatham, Cape Cod in June 2013.

The objective of the program was to deploy nine dive recorders on grey seals (seven cellphone-linked and two satellite-linked) to gather information on the movement and diving activity of the mammals over the coming months. The transmitters record information on location and diving activity while the mammals are at sea and then transmit this information to a cellphone tower or satellite when the seals are within range. Information from the satellite linked transmitters is downloaded via the ARGOS system.

Fifteen mammals were sampled and given numbered flipper tags for identification. Nine were further fitted with a GPS or satellite tag that will provide information over time about where they go and how long they stay there. Two animals captured on different days had deep lacerations around their necks caused by fishing nets that were still present. Both entangled animals were treated for their wounds and released.

Biological samples were also taken as part of a health monitoring program supported by NOAA. Samples included blood, whiskers, fur, mucus swabs, teeth, and small amounts of skin and blubber. Animals that were sedated for sampling were fitted with a heart monitor that also recorded body temperature.

The research work was a collaborative effort led by NOAA’s Northeast Fisheries Science Center. The Riverhead Foundation for Marine Research and Preservation managed field operations and coordinated the biological sampling. Duke University handled the GPS cell tagging and biopsy sampling. Fisheries and Oceans Canada brought its expertise in grey seal handling and sedation. The International Fund for Animal Welfare and Woods Hole Oceanographic Institution provided the project veterinarian and helped with animal monitoring. This initial project was considered a success and additional collaborative efforts are expected in the future.

For more information:
Scientists to Try Cape Cod's First Tagging and Sampling Effort on Adult Gray Seals
Press release, Northeast Fisheries Science Center, NOAA

Mike Hammill and Jean-François Gosselin
Science