Coastal habitat use by ringed seals Pusa hispida following a regional sea-ice collapse: importance of glacial refugia in a changing Arctic

There has been significant sea ice loss associated with climate change in the Pacific Arctic, with unquantified impacts to the habitat of ice-obligate marine mammals such as ringed seals (Pusa hispida). Ringed seals maintain breathing holes and excavate subnivean lairs on sea ice to provide protection from weather and predators during birthing, nursing, and resting. However, there is limited baseline information on the snow and ice habitat, distribution, density, and configuration of ringed seal structures (breathing holes, simple haul-out lairs, and pup lairs) in Alaska. Here, we describe historic field records from two regions of the eastern Chukchi Sea (Kotzebue Sound and Ledyard Bay) collected during spring 1983 and 1984 to quantify baseline ringed seal breeding habitat and map the distribution of ringed seal structures using modern geospatial tools. Of 490 structures located on pre-established study grids by trained dogs, 29% were pup lairs (25% in Kotzebue Sound and 33% in Ledyard Bay). Grids in Ledyard Bay had greater overall density of seal structures than those in Kotzebue Sound (8.6 structures/km2 and 7.1 structures/km2), but structures were larger in Kotzebue Sound. Pup lairs were located in closer proximity to other structures and characterized by deeper snow and greater ice deformation than haul-out lairs or simple breathing holes. At pup lairs, snow depths averaged 74.9 cm (range 37–132 cm), with ice relief nearby averaging 76 cm (range 31–183 cm), and ice deformation 29.9% (range 5–80%). We compare our results to similar studies conducted in other geographic regions and discuss our findings in the context of recent declines in extent and duration of seasonal cover of landfast sea ice and snow deposition on sea ice. Ultimately, additional research is needed to understand the effects of recent environmental changes on ringed seals, but our study establishes a baseline upon which future research can measure pup habitat in northwest Alaska.

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Population organisation in reef sharks: new variations in coastal habitat use by mobile marine predators

Marine Ecology Progress Series ◽

10.3354/meps11545 ◽

2016 ◽

Vol 544 ◽

pp. 197-211 ◽

Cited By ~ 12

Author(s):

A Chin ◽

MR Heupel ◽

CA Simpfendorfer ◽

AJ Tobin

Keyword(s):

Habitat Use ◽

Coastal Habitat ◽

Marine Predators ◽

Reef Sharks

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Stable ringed seal (Pusa hispida) demography despite significant habitat change in Svalbard, Norway

Polar Research ◽

10.33265/polar.v40.5391 ◽

2021 ◽

Vol 40 ◽

Author(s):

Magnus Andersen ◽

Kit M. Kovacs ◽

Christian Lydersen

Keyword(s):

Life History ◽

Sea Ice ◽

Close Association ◽

Ringed Seal ◽

Breeding Habitat ◽

Small Scale ◽

Recent Period ◽

Ringed Seals ◽

Time Periods ◽

Circumpolar Arctic

Ringed seals, which are small phocid seals, range across the circumpolar Arctic, and have evolved in close association with sea ice and depend on it for all aspects of their life history. This research study compares age structure, reproductive parameters, body size and condition during three time periods—1981–82 (n = 277), 2002–04 (n = 272) and 2012–18 (n = 212)—to study potential changes in demography in ringed seals in western Svalbard, Norway, an area that has undergone dramatic changes in sea-ice conditions during recent decades. Age distributions for the three time periods were similar, with the exception that the most recent period had a higher proportion of young animals. Age at sexual maturity for both sexes was similar for the two most recent periods, both being lower than in the 1980s. Ovulation rates did not vary significantly among the three periods (range 0.86–0.94). Pregnancy rates were only available for the most recent study period (0.71); this value falls within the range reported from other Arctic regions. Body length showed no clear temporal patterns; males were slightly longer in the most recent period, while females were slightly longer in the first period. Data from May in all periods suggest that body condition has not varied significantly through time. In conclusion, although the ringed seal breeding habitat in Svalbard has declined significantly in recent decades, demographic parameters appear to be largely unaffected. Life-history plasticity in combination with a small-scale regional variation in environmental conditions might explain the lack of changes in demography over time.

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Unusual Predation Attempts of Polar Bears on Ringed Seals in the Southern Beaufort Sea: Possible Significance of Changing Spring Ice Conditions

ARCTIC ◽

10.14430/arctic3 ◽

2009 ◽

Vol 61 (1) ◽

pp. 14 ◽

Cited By ~ 33

Author(s):

Ian Stirling ◽

Evan Richardson ◽

Gregory W. Thiemann ◽

Andrew E. Derocher

Keyword(s):

Sea Ice ◽

Polar Bear ◽

Foraging Behaviour ◽

Open Water ◽

Beaufort Sea ◽

Polar Bears ◽

Ringed Seals ◽

Decadal Scale ◽

Underlying Causes ◽

Ice Conditions

In April and May 2003 through 2006, unusually rough and rafted sea ice extended for several tens of kilometres offshore in the southeastern Beaufort Sea from about Atkinson Point to the Alaska border. Hunting success of polar bears (Ursus maritimus) seeking seals was low despite extensive searching for prey. It is unknown whether seals were less abundant in comparison to other years or less accessible because they maintained breathing holes below rafted ice rather than snowdrifts, or whether some other factor was involved. However, we found 13 sites where polar bears had clawed holes through rafted ice in attempts to capture ringed seals (Phoca hispida) in 2005 through 2006 and another site during an additional research project in 2007. Ice thickness at the 12 sites that we measured averaged 41 cm. These observations, along with cannibalized and starved polar bears found on the sea ice in the same general area in the springs of 2004 through 2006, suggest that during those years, polar bears in the southern Beaufort Sea were nutritionally stressed. Searches made farther north during the same period and using the same methods produced no similar observations near Banks Island or in Amundsen Gulf. A possible underlying ecological explanation is a decadal-scale downturn in seal populations. But a more likely explanation is major changes in the sea-ice and marine environment resulting from record amounts and duration of open water in the Beaufort and Chukchi seas, possibly influenced by climate warming. Because the underlying causes of observed changes in polar bear body condition and foraging behaviour are unknown, further study is warranted.

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