Seasonal Movements and Diving of Ringed Seals, Pusa hispida, in the Western Canadian Arctic, 1999–2001 and 2010–11

Satellite-linked time-depth recorders were deployed on 17 ringed seals in early summer in 1999, 2000, and 2010, near the Inuvialuit community of Ulukhaktok, Northwest Territories, Canada. The main objective was to investigate movements and diving behaviour of ringed seals in the Prince Albert Sound (PAS) and eastern Amundsen Gulf (EAG) regions in relation to season, sex, and age-class. Tags performed well on 16 of 17 tagged seals, with average tracking periods of 256 d (SD 69, range: 134 – 352). Adult and subadult ringed seals traveled considerable distances throughout the open water period (mean = 5844 km, range = 1232 – 9473 km), using vast home ranges during this season, shown with 90 Percent Volume Contours (90 PVC) averaging 122 854 km2 for subadults, 76 658 km2 for adult females, and 21 649 km2 for adult males. Overall, adults spent 69.5% of the observed open water days in foraging/resident mode and 22.8% in traveling mode. The majority (75%) of total observed foraging/resident time was spent in PAS and EAG. Eleven of 12 adults made forays outside EAG and PAS to distant areas, including Prince of Wales Strait (7 seals), Viscount Melville Sound (6), Minto Inlet (4), western Amundsen Gulf (4), and six other zones. During open water season, subadults spent 36.8% traveling and 51.4% foraging/ resident, also mainly in EAG and PAS (61%), but they all traveled to distant zones, eight in total. During winter, all tagged adult females, five of seven adult males, and three of four subadults returned to PAS and EAG to occupy winter home ranges that were on average 15% of the size of the open water home range (mean winter ranges = 1299 km2 for adult males, 3599 km2 for adult females, and 30 499 km2 for subadults). The mean size of the winter home ranges varied by as much as a factor of 10 among the three winters examined. Seal movements were most restricted during the winters with extensive fast ice (1999 – 2000 and 2010 – 11) and least restricted during the winter (2000 – 01) when fast ice did not form in EAG. In winter, adult females made more long, deep dives than either adult males or subadults.Des enregistreurs de profondeur temporelle en liaison avec un satellite ont été déployés sur 17 phoques annelés au début des étés 1999, 2000 et 2010 près de la collectivité inuvialuite d’Ulukhaktok, dans les Territoires du Nord-Ouest, au Canada. L’objectif principal consistait à étudier les déplacements et les comportements de plongée des phoques annelés des régions du détroit de Prince-Albert (DPA) et de la partie est du golfe Amundsen (EGA) en fonction de la saison, du sexe et de la classe d’âge. Les étiquettes ont donné des résultats valables dans le cas de 16 des 17 phoques étiquetés, les périodes moyennes de pistage ayant atteint 256 jours (SD 69, étendue : 134 – 352). Les phoques annelés adultes et jeunes adultes parcouraient des distances considérables pendant la période des eaux libres (moyenne = 5 844 km, étendue = 1 232 – 9 473 km), dans de vastes domaines vitaux au cours de la saison. Les pourcentages du volume des contours de 90 (90 PVC) s’établissaient en moyenne à 122 854 km2 pour les jeunes adultes, à 76 658 km2 pour les femelles adultes et à 21 649 km2 pour les mâles adultes. Dans l’ensemble, les adultes ont passé 69,5 % des journées observées en eaux libres en mode d’alimentation et de résidence, et 22,8 % en mode de déplacement. La majorité (75 %) du temps total observé en mode d’alimentation et de résidence était dans le DPA et l’EGA. Onze adultes sur 12 se sont aventurés en dehors du DPA et de l’EGA pour atteindre des endroits éloignés, dont le détroit du Prince-de-Galles (7 phoques), le détroit du Vicomte de Melville (6), l’anse Mintot (4), l’ouest du golfe Amundsen (4) et six autres zones. Pendant la saison des eaux libres, les jeunes adultes ont passé 36,8 % du temps en mode de déplacement et 51,4 % du temps en mode d’alimentation ou de résidence, également principalement dans le DPG et l’EGA (61 %), mais ils se sont tous rendus dans des zones éloignées, huit en tout. Durant l’hiver, toutes les femelles adultes étiquetées, cinq mâles adultes sur sept et trois jeunes adultes sur quatre sont revenus dans le DPA et l’EGA pour occuper des domaines vitaux hivernaux qui correspondaient, en moyenne, à 15 % de la taille du domaine vital en eaux libres (étendues moyennes des domaines hivernaux = 1 299 km2 pour les mâles adultes, 3 599 km2 pour les femelles adultes et 30 499 km2 pour les jeunes adultes). La taille moyenne des domaines vitaux hivernaux a varié en fonction d’un facteur de 10 au cours des trois hivers à l’étude. Le déplacement des phoques était plus restreint pendant les hivers où la glace était rapide (1999-2000 et 2010-2011) et moins restreint pendant l’hiver (2000-2001) où la glace rapide ne s’est pas formée dans l’EGA. L’hiver, les femelles adultes faisaient plus de plongées longues et profondes que les mâles adultes ou les jeunes adultes

Comparing temporal patterns in body condition of ringed seals living within their core geographic range with those living at the edge

Ecological theory suggests that demographic responses by populations to environmental change vary depending on whether individuals inhabit central or peripheral regions within the species’ geographic range. Here, we tested this prediction by comparing a population of ringed seals Pusa hispida located at high latitudes as part of their core range (core) with a population located at the southern extremity of their range (peripheral). First, we compared the two regions’ environmental trends in timing of sea-ice breakup and freeze-up, open-water duration and the North Atlantic Oscillation (NAO). We found that the core region shifted to progressively warmer conditions in the early 1990s; whereas, in the peripheral region, the warming trend shifted in 1999 to one with no warming trend but high inter-annual variability. Next, we examined how body condition, inferred from blubber depth, responded to temporal changes in sea-ice and climatic variables – variables that have been shown to influence ringed seal demography. Core seals displayed minimal seasonal changes in body condition; whereas peripheral seals displayed a 20–60% amplitude seasonal change in body condition with a phase shift to earlier initiation of fat accumulation and loss. Finally, we tested for interannual differences and found that both core and peripheral seals responded similarly with decreased body condition following more positive NAO. Environmental variables influenced body condition in opposite directions between the two regions with core seals declining in body condition with later spring breakup and shorter open-water duration, whereas peripheral seals showed opposite relationships. Seals living at the core likely benefit from an evolved match between adaptation and environmental variation resulting in dampened seasonal and interannual fluctuations in body condition. Knowledge of how different populations respond to environmental change depending on geographic location within a species range can assist in anticipating population specific responses to climate warming

Biomarkers in ringed seals reveal recent onset of borealization in the high- compared to the mid-latitude Canadian Arctic

This work resulted from the ARISE project (NE/P006035/1), part of the Changing Arctic Ocean program, funded by the UKRI Natural Environment Research Council (NERC).Warming of the Arctic has resulted in environmental and ecological changes, termed borealization, leading to the northward shift of temperate species. Borealization has occurred across all trophic levels, altering the structure of the food web. The onset and rate of borealization likely varies with latitude, depending on local warming and advection of warmer water into the Arctic. In order to assess latitudinal trends in food web structure in the Arctic, we analyzed stable nitrogen isotopes of specific amino acids alongside bulk stable carbon isotopes in ringed seal muscle tissue from the Canadian Arctic Archipelago (high-Arctic) and Southern Baffin Bay (mid-Arctic) from 1990 to 2016. Our results indicate a shift in food web structure in the high-Arctic that has occurred more recently when compared with the mid-Arctic. Specifically, over the past 25 years, the trophic position of ringed seals from the mid-Arctic was largely constant, whereas the trophic position of ringed seals decreased in the high-Arctic, reaching similar values observed in the mid-Arctic in 2015-2016. This suggests a potential shortening of the food chain length in the high-Arctic, possibly driven by changes in zooplankton communities feeding complexity in association with sea ice decline. This study identifies a temporal offset in the timing of borealization in the Canadian Arctic, resulting in different response of food webs to ecological changes, depending on latitude.Publisher PDFPeer reviewe

Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators

Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near‐top trophic‐level marine predators have been little studied in polar regions or with latitude. We quantified the large‐scale latitudinal variation of population‐ and individual‐level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both within‐ and between‐individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width (TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin (Mallotus villosus) and Sand lance (Ammodytes sp.) at lower latitudes and Arctic cod (Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within‐individual component (WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large‐scale spatial variation in ecological opportunity, suggesting species‐specific variation in dietary plasticity to spatial differences in prey resources and environmental conditions in a rapidly changing ecosystem

Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators

Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near‐top trophic‐level marine predators have been little studied in polar regions or with latitude. We quantified the large‐scale latitudinal variation of population‐ and individual‐level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both within‐ and between‐individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width (TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin (Mallotus villosus) and Sand lance (Ammodytes sp.) at lower latitudes and Arctic cod (Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within‐individual component (WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large‐scale spatial variation in ecological opportunity, suggesting species‐specific variation in dietary plasticity to spatial differences in prey resources and environmental conditions in a rapidly changing ecosystem

Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators

Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near-top trophic-level marine predators have been little studied in polar regions or with latitude. We quantified the largescale latitudinal variation of population- and individual-level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both withinand between-individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width (TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin (Mallotus villosus) and Sand lance (Ammodytes sp.) at lower latitudes and Arctic cod (Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within-individual component (WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large-scale spatial variation in ecological opportunity, suggesting species-specific variation in dietary plasticity to spatial differences in prey resources and environmental conditions in a rapidly changing ecosystem

Abundance and species diversity hotspots of tracked marine predators across the North American Arctic

Aim: Climate change is altering marine ecosystems worldwide and is most pronounced in the Arctic. Economic development is increasing leading to more disturbances and pressures on Arctic wildlife. Identifying areas that support higher levels of predator abundance and biodiversity is important for the implementation of targeted conservation measures across the Arctic. Location: Primarily Canadian Arctic marine waters but also parts of the United States, Greenland and Russia. Methods: We compiled the largest data set of existing telemetry data for marine predators in the North American Arctic consisting of 1,283 individuals from 21 species. Data were arranged into four species groups: (a) cetaceans and pinnipeds, (b) polar bears Ursus maritimus (c) seabirds, and (d) fishes to address the following objectives: (a) to identify abundance hotspots for each species group in the summer–autumn and winter–spring; (b) to identify species diversity hotspots across all species groups and extent of overlap with exclusive economic zones; and (c) to perform a gap analysis that assesses amount of overlap between species diversity hotspots with existing protected areas. Results: Abundance and species diversity hotpots during summer–autumn and winter–spring were identified in Baffin Bay, Davis Strait, Hudson Bay, Hudson Strait, Amundsen Gulf, and the Beaufort, Chukchi and Bering seas both within and across species groups. Abundance and species diversity hotpots occurred within the continental slope in summer–autumn and offshore in areas of moving pack ice in winter–spring. Gap analysis revealed that the current level of conservation protection that overlaps species diversity hotspots is low covering only 5% (77,498 km 2 ) in summer–autumn and 7% (83,202 km 2 ) in winter–spring. Main conclusions: We identified several areas of potential importance for Arctic marine predators that could provide policymakers with a starting point for conservation measures given the multitude of threats facing the Arctic. These results are relevant to multilevel and multinational governance to protect this vulnerable ecosystem in our rapidly changing world

Corrigendum to “Environmental and life-history factors influence inter-colony multidimensional niche metrics of a breeding Arctic marine bird” [Sci. Total Environ. 796 (2021) 148935] (Science of the Total Environment (2021) 796, (S0048969721040079), (10.1016/j.scitotenv.2021.148935))

The authors regret that the printed version of the above article contained an omission of an individual deserving of co-authorship. The correct and final version follows. The authors would like to apologise for any inconvenience caused. \u3c Reyd A. Smith1⁎, David J. Yurkowski2, Kyle J.L. Parkinson1, Jérôme Fort3, Holly L. Hennin4, H. Grant Gilchrist4, Keith A. Hobson5, Mark L. Mallory6, Paco Bustamante3, Jóhannis Danielsen7, Svend E. Garbus8, Sveinn A. Hanssen9, Jón Einar Jónsson10, Christopher J. Latty11, Ellen Magnúsdóttir10, Børge Moe9, Glen J. Parsons12, Christian Sonne8, Grigori Tertitski13, and Oliver P. Love1\u3e Windsor, Windsor, Ontario, Canada, N9B 3P4 2 Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada, R3T 2N6 3 Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS – La Rochelle University, La Rochelle, France, FR-17000 4 Environment and Climate Change Canada, Ottawa, Ontario, Canada, K0A 1H0. 5 Western University, London, Ontario, Canada, N6A 3K7 6Acadia University, Wolfville, Nova Scotia, Canada, B4P 2R6 7 Faroe Marine Research Institute, Tórshavn, Faroe Islands, FO-110 8 Aarhus University, Roskilde, Denmark, DK-4000 9 Norwegian Institute for Nature Research, Tromsø, Norway, N-9296 10 University of Iceland\u27s Research Centre at Snæfellsnes, Hafnargata 3, 340, Stykkishólmur, Iceland 11 Arctic National Wildlife Refuge, U.S. Fish and Wildlife Service, Fairbanks, Alaska, United States, 99701 12 Nova Scotia Department of Lands and Forestry, Kentville, Nova Scotia, Canada, B4N 4E5 13 Institute of Geography of the Russian Academy of Sciences, Moscow, Russia, 119017\u3

Marine mammal hotspots across the circumpolar Arctic

Aim: Identify hotspots and areas of high species richness for Arctic marine mammals. Location: Circumpolar Arctic. Methods: A total of 2115 biologging devices were deployed on marine mammals from 13 species in the Arctic from 2005 to 2019. Getis-Ord Gi* hotspots were calculated based on the number of individuals in grid cells for each species and for phyloge-netic groups (nine pinnipeds, three cetaceans, all species) and areas with high spe-cies richness were identified for summer (Jun-Nov), winter (Dec-May) and the entire year. Seasonal habitat differences among species’ hotspots were investigated using Principal Component Analysis. Results: Hotspots and areas with high species richness occurred within the Arctic continental-shelf seas and within the marginal ice zone, particularly in the “Arctic gateways” of the north Atlantic and Pacific oceans. Summer hotspots were generally found further north than winter hotspots, but there were exceptions to this pattern, including bowhead whales in the Greenland-Barents Seas and species with coastal distributions in Svalbard, Norway and East Greenland. Areas with high species rich-ness generally overlapped high-density hotspots. Large regional and seasonal dif-ferences in habitat features of hotspots were found among species but also within species from different regions. Gap analysis (discrepancy between hotspots and IUCN ranges) identified species and regions where more research is required. Main conclusions: This study identified important areas (and habitat types) for Arctic marine mammals using available biotelemetry data. The results herein serve as a benchmark to measure future distributional shifts. Expanded monitoring and teleme-try studies are needed on Arctic species to understand the impacts of climate change and concomitant ecosystem changes (synergistic effects of multiple stressors). While efforts should be made to fill knowledge gaps, including regional gaps and more com-plete sex and age coverage, hotspots identified herein can inform management ef-forts to mitigate the impacts of human activities and ecological changes, including creation of protected areas

High contributions of sea ice derived carbon in polar bear (Ursus maritimus) tissue.

Polar bears (Ursus maritimus) rely upon Arctic sea ice as a physical habitat. Consequently, conservation assessments of polar bears identify the ongoing reduction in sea ice to represent a significant threat to their survival. However, the additional role of sea ice as a potential, indirect, source of energy to bears has been overlooked. Here we used the highly branched isoprenoid lipid biomarker-based index (H-Print) approach in combination with quantitative fatty acid signature analysis to show that sympagic (sea ice-associated), rather than pelagic, carbon contributions dominated the marine component of polar bear diet (72-100%; 99% CI, n = 55), irrespective of differences in diet composition. The lowest mean estimates of sympagic carbon were found in Baffin Bay bears, which were also exposed to the most rapidly increasing open water season. Therefore, our data illustrate that for future Arctic ecosystems that are likely to be characterised by reduced sea ice cover, polar bears will not only be impacted by a change in their physical habitat, but also potentially in the supply of energy to the ecosystems upon which they depend. This data represents the first quantifiable baseline that is critical for the assessment of likely ongoing changes in energy supply to Arctic predators as we move into an increasingly uncertain future for polar ecosystems