Late summer distribution and abundance of ice-associated whales in the Norwegian High Arctic

Abstract

The Arctic is experiencing rapid warming, and resultant sea ice losses represent a serious threat to ice-associated species in the region. This study explored the distribution and abundance of the 3 Arctic resident whale species: narwhals, bowhead and white whales, in the marginal ice zone and into the sea ice north of the Svalbard Archipelago. Line-transect surveys were conducted using a combination of helicopter-based and ship-based efforts in August 2015. Twenty-six sightings, involving 27 bowhead whales and 58 narwhals, occurred along the helicopter transects, while no whales were recorded along ship transects. No white whales were observed during these surveys. After correcting for surface availability, distance sampling produced abundance estimates of 343 (CV = 0.488) bowhead whales and 837 (CV = 0.501) narwhals within the 52 919 km 2 study area. Bowhead whales were predominantly seen close to the ice-edge, whereas narwhals were located deeper into the ice. To contextualize these results within the broader Svalbard cetacean community, all whale sightings from the Norwegian Polar Institute's Svalbard Marine Mammal Sighting Data Base, from the period of the survey, were mapped to compare general distributions. These opportunistic sightings included numerous cetacean species, especially seasonally occurring ones. However, white whales dominated in terms of the numbers of individuals reported. Our results suggest little spatial overlap between seasonally occurring whales and the 3 Arctic resident whales. Bowhead whales and narwhals were tightly associated with sea ice, and white whales were tightly coastal. In contrast, the seasonally occurring species were found over the shelf and along its edges.

Increasing intensities of Anisakis simplex third-stage larvae (L3) in Atlantic salmon of coastal waters of Scotland

“…prevalence and intensity in haddock (Melanogrammus aeglefinus (L.)) [65], and Atlantic cod [66] in populations sampled from the Barents Sea. With the relative abundance of both large whales and dolphins highest in the Faroe-Shetland Channel [67], and a diverse cetacean population in the Barents Sea [68], these results further demonstrate the potential significance of regional definitive host abundance in prevailing A. simplex (s.l.) intensities.…”

Aerial surveys for Antarctic minke whales (Balaenoptera bonaerensis) reveal sea ice dependent distribution patterns

“…Aerial surveys have been proven as a means to survey ice-covered areas at constant survey speeds, with assumed minimal disturbance effects on animal distribution and effectively collecting cetacean sighting data in 0%-100% ice concentrations (Herr et al, 2016;Scheidat et al, 2011;Vacquié-Garcia et al, 2017;Williams, Kelly, et al, 2014). Williams, Kelly, et al (2014) provided first information on relative AMW abundance on both sides of the ice edge, suggesting up to 20% of AMWs of the Weddell Sea were within icecovered waters.…”

New Extralimital Record of a Narwhal (Monodon monoceros) in Europe

“…Loss of sea ice inevitably leads to changes in the Arctic food web Kortsch et al, 2015), including due to increased presence of predators and competitive stress (Ferguson, 2009;Higdon & Ferguson, 2009;Kovacs et al, 2011;Ferguson et al, 2012;Reeves et al, 2014;Breed et al, 2017;Vacquié-Garcia et al, 2017). Sea-ice loss, consequently, is a concern for many species tightly associated with sea ice, including narwhal (International Whaling Commission [IWC], 1997; Laidre & Heide-Jørgensen, 2005;Loeng et al, 2005;Laidre et al, 2008;Moore & Huntington, 2008;Williams et al, 2011;Evans & Bjørge, 2013).…”

“…However, shifts in the distribution and abundance of Arctic cetaceans within their home ranges (Vacquié-Garcia et al, 2017) and observations outside their home ranges could be indications of some of the less obvious and indirect impacts of climate change.…”