Adaptation Actions for a Changing Arctic: Perspectives from the Barents Area

18

Adaptation Actions for a Changing Arctic: Perspectives from the Barents Area

to perceived conflicts with local fisheries.Non-exploitive‘use’of these species takes place via tourism, much of which is cruise- ship based both coastally and in Svalbard (see Section 2.3). All of the circumpolarArctic endemic marine mammal species are permanent residents in the Barents Sea Region, including the polar bear ( Ursus maritimus ), the three ice-affiliated cetaceans (bowhead Balaena mysticetus , narwhal Monodon monoceros , and white whale Delphinapterus leucas ) and the three pinnipeds found throughout the Arctic (ringed seal Pusa hispida , bearded seal Erignathus barbatus and walrus Odobenus rosmarus ). In addition, harp seals are closely associated with the marginal ice zone in the northern Barents Sea during summer and autumn. Breeding takes place in spring on the ice in theWhite Sea and in theWest Ice (north of the island of Jan Mayen). Hooded seals ( Cystophora cristata ) also breed in the West Ice, but their foraging range extends from the Faroe Islands to theArctic Ocean,with high occupancy in FramStrait. White-beaked dolphins ( Lagenorhynchus albirostris ) are also resident throughout the year, and occur broadly spread through the area, from the northern coast of the mainland through to high latitudes during summer. Relatively little is known about their habitat requirements or even their basic biology, although there are thought to number almost 60,000 animals in this population (Øien, 1993). Similarly, little is known about pelagic killer whales ( Orcinus orca ), which occupy ice-edge areas in the Barents Sea from first light to last, but their residency status on a year-round basis is not known because they have never been tracked to determine whether they migrate out of the region in the period with limited light. Ringed seals and bearded seals in Svalbard have experienced major reductions in available breeding habitat since 2006,when sea ice suddenly and unexpectedly declined markedly; the ice has not returned to earlier norms since that time and now rarely forms at all inmost of the west coast fjords in winter.In addition to the basic need for land-fast ice for breeding, ringed seals have a unique requirement in their need for snow accumulation on the sea ice.This species constructs small caves (or lairs) in snow drifts associated with breathing holes in the ice, in which they give birth and rear their pups. Since 2006, virtually no ringed seal pupping has taken place in west coast fjords in Svalbard (Kovacs et al., 2011) and mortality of pups due to polar bear predation in areas with remaining ice has presumably increased (Freitas et al.,2012).In addition to loss of breeding habitat,recent satellite tracking studies have shown significant increases over the past 10 to 15 years in migration distances and changes in the activity budgets of subadult ringed seals during summer feeding excursions.Ringed sealsmust now travel further to reach summer foraging areas in the pack-ice and once there must spendmore time travelling and diving and less time resting at the surface or on the ice.They also do less sympagic feeding and less area restricted searching, which implies that they are spending more energy finding food (Hamilton et al., 2015). Other climate change signals that have been documented for the ice-affiliated species include dramatic declines in the abundance of theWest Ice hooded seal population, in the order of 80% (Øigård et al., 2014).This major decline is undoubtedly linked to overharvesting in the past, but despite protection their decline has continued due to increased predation on pups from polar bears and killer whales because the whelping patch has

puffin) to have increased while the Arctic sister species (Brünnich’s guillemot breeding on Spitsbergen, large gull species, northern fulmar (on Bjørnøya), and kittiwakes in the Norwegian Sea and Barents Sea) have declined. The reasons behind the recent changes in the Barents Sea seabird communities are not well known. However, several studies suggest that changes in food availability, triggered by changes in ocean climate are linked to the declines (Descamps et al., 2013; Erikstad et al., 2013; Myksvoll et al., 2013). Large variations in the preferred fish prey have been documented (Barrett, 2007). In addition to climate-related variations, the fishing industry might also have played a role by inducing predation pressure on pelagic fish species (Gjøsæter, 1995). For some populations, changed patterns of predation from mammalian and avian predators might also be important. For example, the increase in the population of white-tailed eagle ( Haliaeetus albicilla ) might have increased predation pressure on some avian species on the Norwegianmainland (Hipfner et al., 2012) and changed ice conditions in Spitsbergen fjords results in changes in the access of polar fox ( Alopex lagopus ) to islands with breeding colonies of common eider (Mehlum, 2012). For top predators and scavengers such as glaucous gull ( Larus hyperboreus ), bioaccumulation of organochlorine pollutants carried into the Arctic via long-range transport has been linked to population declines (Erikstad and Strøm, 2012). The present dynamics of several seabird populations on mainland Norway and Russia may still be influenced by the legacy of historical harvesting of eggs, chicks and adults from the breeding colonies (e.g. Fauchald et al., 2011). 2.2.2.5 Marine mammals The Barents Sea region contains one of the most species-rich marine mammal communities in the circumpolar Arctic (Laidre et al.,2015),which reflects the high seasonal productivity of this shelf sea as well as the diversity of water masses present. Most marine mammals are high trophic level feeders,with large body sizes and large blubber reserves, which are important for insulation as well as for energy storage. These animals require food resources that are concentrated in time and space at least on a seasonal basis, making them particularly good ecosystem health indicators; they integrate signals of ecosystem change at lower trophic levels and hence are often referred to as ecosystem ‘sentinels’,thus warranting significant attention in climate change assessments. Twenty-one marine mammal species regularly reside in the Barents Sea, at least on a seasonal basis, and 13 of these are full-time residents that breed locally (Table 2.1). Three additional cetacean species are currently classified as vagrants,although these are increasingly regularly sightedwithin the region. Most of the marine mammals in the Barents Sea region have experienced high levels of past exploitation and some are still artificially depressed by these earlier excessive harvests, such that they are included on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species and consequently protected. Currently, only harp seals ( Pagophilus groenlandicus ) and minke whales ( Balaenoptera acutorostrata ) are commercially harvested, both well within sustainable limits. A few marine mammal species are subject to sport hunting in Svalbard or along the mainland coast, and occasionally coastal seals are culled at the county level, owing