Phenology of the Pacific Walrus (Odobenus rosmarus divergens) in Coastal Waters of Wrangel Island: The Impact of the Sea Ice Dynamics

Abstract The kin structure of a species at relatively fine spatial scales impacts broad-scale patterns in genetic structure at the population level. However, kin structure rarely has been elucidated for migratory marine mammals. The Pacific walrus (Odobenus rosmarus divergens) exhibits migratory behavior linked to seasonal patterns in sea ice dynamics. Consequently, information on the spatial genetic structure of the subspecies, including kin structure, could aid wildlife managers in designing future studies to evaluate the impacts of sea ice loss on the subspecies. We sampled 8,303 individual walruses over a 5-year period and used 114 single-nucleotide polymorphisms to examine both broad-scale patterns in genetic structure and fine-scale patterns in relatedness. We did not detect any evidence of genetic structure at broad spatial scales, with low FST values (≤ 0.001) across all pairs of putative aggregations. To evaluate kin structure at fine spatial scales, we defined a walrus group as a cluster of resting individuals that were less than one walrus body length apart. We found weak evidence of kin structure at fine spatial scales, with 3.72% of groups exhibiting mean relatedness values greater than expected by chance, and a significantly higher overall observed mean value of relatedness within groups than expected by chance. Thus, the high spatiotemporal variation in the distribution of resources in the Pacific Arctic environment likely has favored a gregarious social system in Pacific walruses, with unrelated animals forming temporary associations.

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Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers

PLoS ONE ◽

10.1371/journal.pone.0255686 ◽

2021 ◽

Vol 16 (8) ◽

pp. e0255686

Author(s):

Chelsea W. Koch ◽

Lee W. Cooper ◽

Ryan J. Woodland ◽

Jacqueline M. Grebmeier ◽

Karen E. Frey ◽

...

Keyword(s):

Organic Carbon ◽

Sea Ice ◽

Nitrogen Isotopes ◽

Chukchi Sea ◽

Trophic Position ◽

Ice Algae ◽

Pacific Walrus ◽

Odobenus Rosmarus Divergens ◽

Odobenus Rosmarus ◽

The Pacific

The expected reduction of ice algae with declining sea ice may prove to be detrimental to the Pacific Arctic ecosystem. Benthic organisms that rely on sea ice organic carbon (iPOC) sustain benthic predators such as the Pacific walrus (Odobenus rosmarus divergens). The ability to track the trophic transfer of iPOC is critical to understanding its value in the food web, but prior methods have lacked the required source specificity. We analyzed the H-Print index, based on biomarkers of ice algae versus phytoplankton contributions to organic carbon in marine predators, in Pacific walrus livers collected in 2012, 2014 and 2016 from the Northern Bering Sea (NBS) and Chukchi Sea. We paired these measurements with stable nitrogen isotopes (δ15N) to estimate trophic position. We observed differences in the contribution of iPOC in Pacific walrus diet between regions, sexes, and age classes. Specifically, the contribution of iPOC to the diet of Pacific walruses was higher in the Chukchi Sea (52%) compared to the NBS (30%). This regional difference is consistent with longer annual sea ice persistence in the Chukchi Sea. Within the NBS, the contribution of iPOC to walrus spring diet was higher in females (~45%) compared to males (~30%) for each year (p < 0.001), likely due to specific foraging behavior of females to support energetic demands associated with pregnancy and lactation. Within the Chukchi Sea, the iPOC contribution was similar between males and females, yet higher in juveniles than in adults. Despite differences in the origin of organic carbon fueling the system (sea ice versus pelagic derived carbon), the trophic position of adult female Pacific walruses was similar between the NBS and Chukchi Sea (3.2 and 3.5, respectively), supporting similar diets (i.e. clams). Given the higher quality of organic carbon from ice algae, the retreat of seasonal sea ice in recent decades may create an additional vulnerability for female and juvenile Pacific walruses and should be considered in management of the species.

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The impact of sea-ice dynamics on the Arctic climate system

Climate Dynamics ◽

10.1007/s00382-003-0309-5 ◽

2003 ◽

Vol 20 (7-8) ◽

pp. 741-757 ◽

Cited By ~ 38

Author(s):

S. Vavrus ◽

S. P. Harrison

Keyword(s):

Sea Ice ◽

Climate System ◽

Arctic Climate ◽

The Arctic ◽

Ice Dynamics ◽

Sea Ice Dynamics ◽

The Impact

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Observations on keeping the Pacific walrus Odobenus rosmarus divergens at Hanover Zoo

International Zoo Yearbook ◽

10.1111/j.1748-1090.1987.tb03153.x ◽

2007 ◽

Vol 26 (1) ◽

pp. 163-170 ◽

Cited By ~ 2

Author(s):

LOTHAR DITTRICH

Keyword(s):

Pacific Walrus ◽

Odobenus Rosmarus Divergens ◽

Odobenus Rosmarus ◽

The Pacific

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Novel sound production through contingency learning in the Pacific walrus (Odobenus rosmarus divergens)

Animal Cognition ◽

10.1007/s10071-007-0120-5 ◽

2007 ◽

Vol 11 (2) ◽

pp. 319-327 ◽

Cited By ~ 20

Author(s):

Ronald J. Schusterman ◽

Colleen Reichmuth

Keyword(s):

Sound Production ◽

Contingency Learning ◽

Pacific Walrus ◽

Odobenus Rosmarus Divergens ◽

Odobenus Rosmarus ◽

The Pacific

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Impact of wave-induced sea ice fragmentation on sea ice dynamics in the MIZ

10.5194/egusphere-egu2020-8657 ◽

2020 ◽

Author(s):

Guillaume Boutin ◽

Timothy Williams ◽

Pierre Rampal ◽

Einar Olason ◽

Camille Lique

Keyword(s):

Sea Ice ◽

Barents Sea ◽

Ice Cover ◽

Arctic Sea Ice ◽

The Arctic ◽

Sea Ice Extent ◽

Ice Dynamics ◽

Sea Ice Dynamics ◽

Wave Induced ◽

The Impact

The decrease in Arctic sea ice extent is associated with an increase of the area where sea ice and open ocean interact, commonly referred to as the Marginal Ice Zone (MIZ). In this area, sea ice is particularly exposed to waves that can penetrate over tens to hundreds of kilometres into the ice cover. Waves are known to play a major role in the fragmentation of sea ice in the MIZ, and the interactions between wave-induced sea ice fragmentation and lateral melting have received particular attention in recent years. The impact of this fragmentation on sea ice dynamics, however, remains mostly unknown, although it is thought that fragmented sea ice experiences less resistance to deformation than pack ice. In this presentation, we will introduce a new coupled framework involving the spectral wave model WAVEWATCH III and the sea ice model neXtSIM, which includes a Maxwell-Elasto Brittle rheology. We use this coupled modelling system to investigate the potential impact of wave-induced sea ice fragmentation on sea ice dynamics. Focusing on the Barents Sea, we find that the decrease of the internal stress of sea ice resulting from its fragmentation by waves results in a more dynamical MIZ, in particular in areas where sea ice is compact. Sea ice drift is enhanced for both on-ice and off-ice wind conditions. Our results stress the importance of considering wave&#8211;sea-ice interactions for forecast applications. They also suggest that waves likely modulate the area of sea ice that is advected away from the pack by ocean (sub-)mesoscale eddies near the ice edge, potentially contributing to the observed past, current and future sea ice cover decline in the Arctic.&#160;

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Mating Behaviors Exhibited by a Captive Male Pacific Walrus (Odobenus rosmarus divergens)

International Journal of Comparative Psychology ◽

10.46867/ijcp.2016.29.00.18 ◽

2016 ◽

Vol 29 ◽

Author(s):

Jessica M McCord ◽

Erin E. Frick ◽

Dianne Cameron ◽

Stan A. Kuczaj II

Keyword(s):

Behavioral Repertoire ◽

Pacific Walrus ◽

Odobenus Rosmarus Divergens ◽

Odobenus Rosmarus ◽

The Pacific ◽

In The Wild ◽

Mating Behaviors ◽

Present Case Study ◽

Future Management

The population of the Pacific walrus (Odobenus rosmarus divergens) is currently a topic of conservation efforts. Understanding the mating behaviors of a species can be utilized in conservation efforts to preserve the species. Little is known about the behavioral repertoire of Pacific walruses, due to their isolated Arctic habitats, with limited studies previously describing observations of walrus mating behaviors. The aim of the present case study was to observe the mating behaviors of a single captive male Pacific walrus to examine overall frequency of specific mating behaviors in both social and solitary contexts. The subjects, one male and two females, were recorded at Six Flags Discovery Kingdom from November 2013 through January 2014. Only behaviors exhibited by the male walrus directly associated with mating were noted. Grabs were the most frequently observed behavior, and holds were not significantly observed which could contribute to the infrequent successful copulation attempts. Pharyngeal sac inflation, a vocal and visual behavior, was not frequently observed in a sexual context but has been observed in mating contexts in the wild. The male walrus used other sexual outlets such as self-gratification and toy use; however, these behaviors occurred significantly less than sexual encounters with females. There appeared to be a mate preference for the female with tusks, as the male interacted significantly more with the tusked female compared to the non-tusked female who was in estrus. Studying mating behavior in controlled settings such as this can be revealing of the capabilities of the species as a whole. Understanding more about how walruses interact in their environment can be used for future management and breeding strategies.

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Wave–sea-ice interactions in a brittle rheological framework

10.5194/tc-2020-19 ◽

2020 ◽

Author(s):

Guillaume Boutin ◽

Timothy Williams ◽

Pierre Rampal ◽

Einar Olason ◽

Camille Lique

Keyword(s):

Sea Ice ◽

Barents Sea ◽

Ice Cover ◽

Arctic Sea Ice ◽

The Arctic ◽

Sea Ice Extent ◽

Ice Dynamics ◽

Sea Ice Dynamics ◽

Wave Induced ◽

The Impact

Abstract. The decrease in Arctic sea ice extent is associated with an increase of the area where sea ice and open ocean interact, commonly referred to as the Marginal Ice Zone (MIZ). In this area, sea ice is particularly exposed to waves that can penetrate over tens to hundreds of kilometres into the ice cover. Waves are known to play a major role in the fragmentation of sea ice in the MIZ, and the interactions between wave-induced sea ice fragmentation and lateral melting have received particular attention in recent years. The impact of this fragmentation on sea ice dynamics, however, remains mostly unknown, although it is thought that fragmented sea ice experiences less resistance to deformation than pack ice. Here, we introduce a new coupled framework involving the spectral wave model WAVEWATCH III and the sea ice model neXtSIM, which includes a Maxwell-Elasto Brittle rheology. We use this coupled modelling system to investigate the potential impact of wave-induced sea ice fragmentation on sea ice dynamics. Focusing on the Barents Sea, we find that the decrease of the internal stress of sea ice resulting from its fragmentation by waves results in a more dynamical MIZ, in particular in areas where sea ice is compact. Sea ice drift is enhanced for both on-ice and off-ice wind conditions. Our results stress the importance of considering wave–sea-ice interactions for forecast applications. They also suggest that waves likely modulate the area of sea ice that is advected away from the pack by ocean (sub-)mesoscale eddies near the ice edge, potentially contributing to the observed past, current and future sea ice cover decline in the Arctic.

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A new coupled model to shed light on sea-ice--ocean interactions

10.5194/egusphere-egu21-10122 ◽

2021 ◽

Author(s):

Guillaume Boutin ◽

Einar Ólason ◽

Pierre Rampal ◽

Camille Lique ◽

Claude Talandier ◽

...

Keyword(s):

Sea Ice ◽

Numerical Models ◽

Coupled Model ◽

Small Scale ◽

Polar Regions ◽

Fine Scale ◽

Ice Dynamics ◽

Damage Propagation ◽

Sea Ice Dynamics ◽

The Impact

Sea ice is a key component of the earth&#8217;s climate system as it modulates air-sea interactions in polar regions. These interactions strongly depend on openings in the sea ice cover, which are associated with fine-scale sea ice deformations. Visco-plastic sea ice rheologies used in most numerical models struggle at representing these fine-scale sea ice dynamics without going to very costly horizontal resolutions (~1km). A solution is to use damage propagation sea ice models, which were shown to reproduce well sea ice deformations with little dependency on the mesh resolution.&#160;Here we present results from the first ocean--sea-ice coupled model using a rheology with damage propagation. The ocean component is the NEMO-OPA model. The sea ice component is neXtSIM, introducing the newly developed Brittle Bingham-Maxwell rheology. Results show that sea ice dynamics are very well represented from large scales (sea ice drift) to small-scales (sea ice deformation). Sea ice properties relevant for climate, i.e volume and area, also show a remarkable match with satellite observations. This coupled framework opens new opportunities to quantify the impact of small-scale sea ice dynamics on ice-ocean interactions.

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