Status, genetic diversity and stock identity of Spitsbergen bowhead whales
In cooperation with: Norwegian Polar Institute, Greenland Institute of Natural Resources, and Fisheries and Oceans (Canada)
Bowhead whales inhabit Arctic and sub-Arctic seas and five geographic stocks are recognised in the Bering-Chukchi-Beaufort (BCB) Seas, Okhotsk Sea, Davis Strait/Baffin Bay, Hudson Bay/Foxe Basin, and in the areas around Svalbard (Spitsbergen). Most evidence for stock identification is indirect and circumstantial. Due to exploitation over several centuries the bowhead whale went nearly extinct in most of its former range. The pre-exploitation stock size in the Svalbard area has been estimated to 25,000. After cessation of the hunt in 1932, the Spitsbergen stock was considered extinct. The population size of bowhead whales now shows a trend to increase. In the Northeast Atlantic, sporadic but persistent observations have been made within the assumed distribution range of the Spitsbergen stock. In April 2006 we observed up to 20 bowhead whales in the Fram Strait supposedly belonging to the Spitsbergen stock.
Large-scale fluctuations in distribution and abundance of bowhead whales have affected stock structure and genetic diversity over time. In a recent study we have used mtDNA extracted from old bones to investigate temporal genetic variation of bowhead whales from Svalbard in the period 50,000 years BP to the present. We found no difference in genetic structure between the Svalbard Holocene samples and the contemporary Bering Strait stock. Our results challenge the current designation of five distinct bowhead whale stocks in the Arctic.
In the present project we will survey the Fram Strait for bowhead whales by help of the ice going research vessel “Lance”. We will take skin samples for genetic analyses. We will compare the genetic constitution of the Holocene stock of bowheads at Svalbard with present day individuals in the Svalbard area and with several hundred skin samples collected in West Greenland since 2000. The principal objective of the proposed project is a comprehensive approach to the population structure and the genetic diversity of the Spitsbergen stock of bowhead whales, and to assess the relationships to other stocks.