Distribution and habitat characteristics of pinnipeds and polar bears in the Svalbard Archipelago, 2005–2018

This study presents comprehensive mapping of the current distribution of pinnipeds and polar bears (Ursus maritimus) around Svalbard based on a regional marine mammal sightings programme and explores time-trends (2005–2018). Walruses (Odobenus rosmarus) were observed with high frequency and in high numbers around previously identified haul-out sites. At-sea walruses were seen close to the coast in shallow waters. Ringed seals (Pusa hispida) were observed in coastal areas throughout Svalbard, often in association with tidewater glacier fronts. There was no increase in the mean latitude for ringed seal observations, but there was an increased frequency of observations at around 82°N, which reflects their following a northward shift in the ice edge during summer foraging trips. Bearded seals (Erignathus barbatus) were observed frequently in north-western Spitsbergen and shared many habitat features with ringed seals. There was a slight increase in the mean latitude of bearded seal observations and a decreased frequency of observation in the southern parts of the archipelago, suggesting that this species might be shifting its distribution. Harbour seal (Phoca vitulina) observations within fjords have increased, likely as a consequence of increased inflow of Atlantic water into west coast fjords. Harp seals (Pagophilus groenlandicus) were observed with high frequency north of Svalbard. Hooded seals (Cystophora cristata) were observed only rarely. Polar bears were reported most frequently, undoubtedly as a result of an effort bias favouring this species. In spite of biases, citizen-based observations are useful for assessing broad distributional patterns of marine mammals through time.