A review of the ecology and status of white whales (Delphinapterus leucas) in Svalbard, Norway

Abstract

The Norwegian Polar Institute initiated a research programme on white whales in 1995 to gather biological information relevant for the species’ management; the results of which are reviewed herein. Satellite tracking from two periods (1995–2001 and 2013–16), between which sea ice diminished markedly, showed that the whales in waters off the archipelago of Svalbard spent most of their time foraging close to tidewater glaciers. Transits between glaciers typically followed the coastline, with the whales moving rapidly from one glacier to another. During the later period, the whales spent some time out in the fjords, suggesting that they might be targeting prey in the Atlantic Water masses that now prevail in Svalbard’s west-coast fjords. Most of their dives were extremely shallow (13 ± 26 m; maximum 350 m) and of short duration (97 ± 123 s; maximum 31.4 min). Fatty-acid analyses indicated that polar cod (Boreogadus saida) was the main prey during the first sampling period. An aerial survey in 2018 estimated the population numbered 549 (CI: 436–723) animals. Svalbard white whales are genetically separate from populations off west Greenland and in the White Sea. Predation by killer whales appears to have influenced white whale behaviour in Svalbard; they are often silent, despite having a normal vocal repertoire for the species and their coastal movements take place in very shallow water. This population has extremely high contaminant levels. Climate change poses a threat to this small population of white whales.