Marine mammal hotspots in the Greenland and Barents Seas

Abstract

Environmental change and increasing levels of human activity are threats to marine mammals in the Arctic. Identifying marine mammal hotspots and areas of high species richness are essential to help guide management and conservation efforts. Herein, space use based on biotelemetric tracking devices deployed on 13 species (ringed seal Pusa hispida, bearded seal Erignathus barbatus, harbour seal Phoca vitulina, walrus Odobenus rosmarus, harp seal Pagophilus groenlandicus, hooded seal Cystophora cristata, polar bear Ursus maritimus, bowhead whale Balaena mysticetus, narwhal Monodon monoceros, white whale Delphinapterus leucas, blue whale Balaenoptera musculus, fin whale Balaenoptera physalus and humpback whale Megaptera novaeangliae; total = 585 individuals) in the Greenland and northern Barents Seas between 2005 and 2018 is reported. Getis-Ord Gi* hotspots were calculated for each species as well as all species combined, and areas of high species richness were identified for summer/autumn (Jun-Dec), winter/spring (Jan-May) and the entire year. The marginal ice zone (MIZ) of the Greenland Sea and northern Barents Sea, the waters surrounding the Svalbard Archipelago and a few Northeast Greenland coastal sites were identified as key marine mammal hotspots and areas of high species richness in this region. Individual hotspots identified areas important for most of the tagged animals, such as common resting, nursing, moulting and foraging areas. Location hotspots identified areas heavily used by segments of the tagged populations, including denning areas for polar bears and foraging areas. The hotspots identified herein are also important habitats for seabirds and fishes, and thus conservation and management measures targeting these regions would benefit multiple groups of Arctic animals.

Ice-algal carbon supports harp and ringed seal diets in the European Arctic: evidence from fatty acid and stable isotope markers

“…Regard-less of these changes, sea ice is still seasonally present within the European Arctic, and both harp and ringed seals continue to associate with this habitat. Their continued association with sea ice is reflected in their foraging behavior (Hamilton et al 2016(Hamilton et al , 2021 and migratory patterns (Stenson et al 2020), and is still apparent in the carbon sourcing to their diet (the present study). Given the current state of sea-ice loss in the Northern Barents Sea (Perovich et al 2020), it remains to be seen if these seals will transition to a more open-water dominated lifestyle and diet, opt for potentially longer migration routes to the ice edge, or experience population size declines.…”

“…Niche partitioning theory states that species coexisting in the same foraging space are expected to have different diets or resource use, effectively limiting competition (MacArthur 1958). In the European Arctic, harp (Pagophilus groenlandicus) and ringed (Pusa hispida) seals are found in similar habitats for at least part of the year, along the sea-ice edge and in coastal Svalbard waters during spring and summer (Hamilton et al 2021). They often target similar ice-associated prey (Nilssen et al 1995b, Labansen et al 2007), but exhibit some niche separation via differences in foraging behavior (dive depth, size of prey selected; Wathne et al 2000).…”

Increases in Benthic Particulate Export and Sedimentary Denitrification in the Northern Chukchi Sea Tied to Under‐Ice Primary Production

“…Arrigo and Van Dijken (2015) hypothesized that phytoplankton in the Chukchi Sea were able to consume a greater proportion of available $${\text{NO}}_{3}^{-}$$, reducing $${\text{NO}}_{3}^{-}$$ availability and consequently NPP in the N‐limited Greenland Sea (Krisch et al., 2020). Reductions in NPP in regions downstream of the Chukchi Sea could substantially limit food available to zooplankton, pelagic fish, marine mammals, and seabirds (Hamilton et al., 2021; Joiris, 2011; Munk, 2003; Rysgaard et al., 1999). Additionally, the Chukchi shelf has some of the lowest N* values (a measure of N excess relative to phosphorus; Gruber & Sarmiento, 1997) in the global ocean (Deutsch & Weber, 2012), driven by high sedimentary denitrification (Brown et al., 2015; Chang & Devol, 2009; Devol et al., 1997; Mills et al., 2015).…”

Eavesdropping at the Speed of Light: Distributed Acoustic Sensing of Baleen Whales in the Arctic

“…In the Arctic, the climate is changing faster than anywhere else in the world. It has been linked to major shifts in species distributions related to sea-ice loss and the Atlantification of the region (Hamilton et al, 2021). In the high latitudes of the Svalbard archipelago, boreal species, e.g., blue whales (balaenoptera musculus), fin whales (balaenoptera physalus), humpback (megaptera novaeangliae) and sei whales (balaenoptera borealis), have been considered seasonal residents, traditionally present from late spring/early summer to the fall and spending their winters at lower latitudes (Moore et al, 2019).…”

“…Furthermore, with sea-ice loss came an increase in human activities. While ship traffic is already abundant between the Barents and North sea and Svalbard (Reeves et al, 2014;Eguıĺuz et al, 2016), it will likely intensify in species-rich areas (Hamilton et al, 2021) with the impending cross-Arctic shipping routes (Ng et al, 2018). Airgun signals can already be recorded all year round in the western Fram Strait (Ahonen et al, 2017).…”