Research on ringed seal populations in Greenland has been ongoing for many years, and has been increasing since the early 1970s. Early research focused on monitoring the harvest (catch statistics, life history parameters, diet, contaminants), and then expanded to studying ringed seal movements, both using conventional tagging and satellite tracking. Later on distribution and abundance surveys were also conducted. Prominent in these research efforts has been the Greenland Institute of Natural Resources (GINR) in collaboration with the Danish National Environmental Research Institute, now the Danish Center for Environment and Energy (DCE) from Aarhus Universitet.
A tagging programme of ringed seals was initiated in September 2010 by the GINR in collaboration with DCE and hunters as part of a series of environmental studies in advance of possible hydrocarbon development. One ringed seal was instrumented in September 2010 at Cape Farewell and 12 ringed seal were instrumented in 2011 in Melville Bay, Northwest Greenland.
Tagging studies have provided information on ringed seal behaviour, which can differ significantly in different areas. Some places hold a high concentration of local stationary seals, whereas other areas have many migratory seals that swim long distances. It is a large and expensive task to identify the movement patterns of ringed seals throughout their distribution area. Fortunately for this research, oceanographers have become aware that satellite transmitters on seals can also be used to gather data on water temperature and salinity down through the water column when the seal dives (temperature and salinity profiles). The ringed seal is particularly useful because many ringed seals live in ice-filled waters where it can be impossible or very expensive and difficult to get around by boat. A new tagging programme was therefore initiated in 2010 for obtaining oceanographic data in the vicinity of outlet glaciers along the cost of Greenland (the Icefjord in Ilulissat in west Greenland, Cape Farewell in South Greenland and Helheim in East Greenland). The project is a collaboration between physical oceanographers from New York University (NYU) and biological oceanographers from GINR and the Sea Mammal Research Unit (UK). The specific purposes
of the project are to further the understanding of the hydrographic conditions of the waters near the outlet glaciers along the coast of Greenland, and the behaviour of ringed seals that in habitat the fjords in such areas. From 2010 to 2013, 13 seals were instrumented with satellite relay data loggers (SRDLs) which can measure Conductivity/Temperature/Depth (CTD). The project continued in 2014 and is funded for at least 4 more years. The movements of the seals as well as the profiles collected can be seen here.
The collection of stomach samples and other tissues from the seal harvest in Aappilattoq, Cape Farewell, was initiated in the fall of 2009 and continued throughout 2010. The project’s aim was to identify the diet of seals in these areas and to look into ecological interactions. The location was chosen partly because all five species of seals common in Greenland are harvested there. All the practical aspects of this project were run by local people. Studies of contaminants in seals in West Greenland are carried out by DCE.
A large ringed seal from Kangia (Jacobshavn Icefjord) with data-logger. Photo: A. Rosing-Asvid
Scientists A. Rosing-Asvid (GINR) and D. Holland (NYU), inspecting equipment; the (green) seal capture/release net can be seen on the lower right. Photo: D. Holland
Ringed seals in Svalbard have been the subject of research efforts in a wide variety of subject areas, intermittently since the early 1980s. Prominent in these research efforts has been the Norwegian Polar Institute (NPI), which has been looking at population parameters, diet, habitat use, reproductive and general ecology, reproductive energetics, abundance at different fjords, diving behavior and physiology, and contaminant burdens. This body of research provides the basis for a meaningful data time series that will permit assessment of population and ecological trends.
In 2002 NPI began a dedicated monitoring programme for ringed seals as part of MOSJ (Monitoring of Svalbard and Jan Mayen), designed to explore important aspects of ringed seal population biology and ecology and provide the first comparative data in a time series for the population (Kovacs and Lydersen 2006). It focuses on density and abundance of ringed seals in selected fjords, trends in population parameters (age structure and vital rates), diet, genetics, condition and ‘health status’ (blubber-reserves, serum chemistry, parasite infestations), and contaminant burdens (POPs, heavy metals, toxaphenes).
The project ICE Ecosystems is a research programme that focuses on Arctic species that are dependent on ice in some part of their life cycles and are threatened by future climate change: ice fauna, zooplankton, polar cod, polar bears, ringed seals and ivory gulls. As part of the ICE ringed seal programme from 2010 to 2012, 38 ringed seals off Svalbard were instrumented with advanced satellite tags to get information on the life of the seals and their use of the sea ice outside the breeding and moulting periods. The satellite tags used in this research programme provide the standard information on where the seals are, how deep they are diving and for how long, but in addition they provide hydrographic data (salinity and temperature) as well as information that gives insight into primary production (chlorophyll levels) in the regions where the seals swim and dive. The field reports for the field season 2012 can be accessed here and here. Samples have also been collected in Kongsfjorden, for various ecotoxicological studies.
In 2013 tagging continued using various combinations of satellite tags and sensors that were deployed on males and females of different age classes. Data collection ended and analysis is underway. Sea ice has continued to decline markedly within the archipelago in recent years, with no sea ice formation at all taking place in most of Svalbard’s fjords in the winter of 2011 and spring of 2012. Instrumented animals tracked via ARGOs and GPS systems will document their responses to these unique conditions, which are likely precursors of what ringed seals will experience elsewhere in the decades to come (Lydersen and Kovacs, in Kovacs 2014).
Fitting a satellite tag to a ringed seal back at Svalbard. Scientists K. M. Kovacs and C. Hamilton (NPI) sitting over a ringed seal while gluing a satellite tag to its fur (left) prior to its release (right). Photo: K.M. Kovacs and C. Lydersen / Norwegian Polar Institute, from ICE Ringed seals - 2nd field report.