Research carried out by Greenland has included the collection and analysis of samples for genetic studies, the application of satellite tags, and abundance surveys. The latter have provided important information on the size of the population of whales wintering off West Greenland, and the trends in abundance over time. Ten surveys have been carried out off West Greenland since 1981, and most recently in 2008 (Heide-Jørgensen and Acquarone 2002, Heide-Jørgensen et al. 2010, NAMMCO 2010). These surveys have covered an area from Disko Island in the north, south as far as Paamiut in some years, from short out to as far as 80km from the coast. The surveys have been conducted by aircraft, using experienced observers who record data using distance sampling techniques. The more recent surveys have also used video and still photography to record ice and environmental conditions, and to collect images of whales.
It is rare to have over 30 years of survey data on distribution and abundance of any species, and this provides a rich source of data for assessing the possible impacts of a changing climate on an Arctic species. Heide-Jørgensen et al. (2010) use these surveys to demonstrate the recent trend towards lighter winter ice cover off West Greenland has led to a shift in beluga distribution to more offshore areas. Beluga apparently take advantage of the reduced ice cover offshore to access areas that were inaccessible to them in previous years. This offers hope that this species might be flexible enough to adapt to a rapidly changing climate.
Greenland has also been involved in elucidating the seasonal movements of belugas through the use of satellite-linked transmitter/receivers. These compact devices, often referred to as “satellite tags”, are attached to captured whales which are then released. The tags collect data on diving behaviour and movements, which are transmitted via satellite during the brief period when the tag breaches the sea surface.
Beluga whales are usually captured by isolating individuals or small groups and driving them slowly to shore using small boats. The whales are then immobilized on the beach using nets and ropes, and the tag is surgically attached to the dorsal ridge. The tags transmit for 2-3 months on average; communication with the tag is lost once it falls off the whale (Richard et al. 2001).
|Applying a saddle tag to a beluga. The tag is attached using plastic bolts through the dorsal ridge. It transmits data to a satellite when the whale surfaces. The tags fall off usually in less than 6 months. Photo: Greenland Institute of Natural Resources.|
While it has proven difficult to tag beluga during their winter occupation of West Greenland waters, Greenland researchers have been involved in tagging operations in Arctic Canada. These applications have demonstrated conclusively that some belugas that summer in Arctic Canada do migrate to West Greenland for the winter (Richard et al. 2001). The tags have also provided important data on diving that has been used to derive correction factors for aerial surveys.
Similar techniques have been used by Norwegian researchers to monitor the movements and diving behaviour of beluga around Svalbard. Here belugas do not seem to make long-distance migrations, remaining within the archipelago throughout most of the year (Lydersen et al. 2001). An innovative application of tagging was to use belugas as oceanographic “adaptive samplers” to monitor temperature and salinity in areas that are normally inaccessible to research vessels because of ice conditions (Lydersen et al. 2002).
|Tagging a beluga in Svalbard, Norway. Photos: K.M. Kovacs and C. Lydersen, Norwegian Polar Institute.|
Greenland researchers have also been heavily involved in genetic studies of beluga populations. These studies use small samples collected from beluga hunts, tagging operations and in some cases, biopsies. While the social structure of beluga populations has made the interpretation of genetic data challenging (de March et al. 2002, Palsbøll et al. 2002), genetic studies have been successful in discriminating the major divisions in beluga populations.