Spring diet of ringed seals (Phoca hispida) from northwestern Spitsbergen, Norway

Scavenging amphipods are important for the circulation and dispersal of organic material in the marine environment. Despite their dominance in the scavenging guild and importance in the food web, little is known about Arctic amphipods and their feeding preferences. We studied the amphipod scavenging guild using baited traps for one full year to increase our understanding of its seasonal variations. Two Arctic fjords with contrasting hydrographical conditions were studied: Adventfjorden, which is influenced by Atlantic water inflow, and Rijpfjorden, which is dominated by cold Arctic water masses. The species composition clearly differed between the 2 fjords. Onisimus caricus, followed by Anonyx laticoxae, were the dominant species in Adventfjorden. In Rijpfjorden, the species diversity was higher, particularly for Anonyx spp. In both fjords, a clear depth zonation in species distribution was detected, with a seasonal dynamic in species composition. A seasonal pattern in catch sizes was observed in both fjords. The timing of this pattern varied, likely because of the climatic differences between the fjords. Lipid content, lipid classes and fatty acid composition were analyzed for A. nugax, O. caricus, O. litoralis, O. nanseni and O. glacialis, and stable isotopes were also analyzed for the all these species except O. glacialis. A clear difference in the fatty acid and stable isotope composition was found among species. O. glacialis and O. litoralis were primarily omnivorous-herbivorous, while the other species were predominantly carnivorous. O. nanseni and A. nugax preyed extensively on calanoid copepods (Calanus spp.) whereas O. caricus did not.

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“…obs.). The predation pressure on amphipods by fish and seals (Labansen et al 2007) remains unknown in our study area.…”

Section: Seasonality In the Trap Catchesmentioning

confidence: 92%

The amphipod scavenging guild in two Arctic fjords: seasonal variations, abundance and trophic interactions

Nygård¹,

Berge²,

Søreide³

et al. 2012

Aquat. Biol.

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“…and capelin Mallotus villosus, with diet varying by age, space (e.g. Lowry et al 1980, Labansen et al 2007, Yurkowski et al 2016a) and season (e.g. Siegstad et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Influence of sea ice phenology on the movement ecology of ringed seals across their latitudinal range

Yurkowski¹,

Semeniuk²,

Harwood³

et al. 2016

Mar. Ecol. Prog. Ser.

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Environmental variation influences resource distribution, thereby affecting animal movement and foraging decisions. Climate change is altering environmental processes worldwide, but particularly in the Arctic, where changes in the phenology of sea ice have been redistributing resources across space and time. How polar marine predators such as ringed seals Pusa hispida hispida, whose ecology is tightly tied to sea ice, respond to different sea ice dynamics across large spatial scales is generally unknown. Here, behavioural states (resident and traveling) were estimated using state−space models on adult (n = 45) and subadult (n = 85) ringed seal satellite telemetry tracks from 6 Arctic locations. Tagged ringed seals spanned a wide latitudinal (56.54° to 75.58°N) and sea ice phenological range from short (1 to 2 mo) to longer (6 mo) ice-free periods. We assessed the influences of age class and several intra-and inter-annual environmental variables on ringed seal movement ecology. Both adults and subadults spent most of the icefree season in a resident state (93 and 77%, respectively). A latitudinal gradient was characterised, where longer ice-free seasons and less inter-annual variability in sea ice phenology at lower latitudes were related to ringed seals spending more time in a resident state than their conspecifics at higher latitudes (90 versus 58%, respectively), where the ice-free season was shorter and sea ice phenology between years was less synchronous. Ringed seals are responding to latitudinal differences in sea ice phenology which affect prey distribution, suggesting plasticity in their foraging decisions and spatiotemporal differences in prey distribution across the rapidly changing Arctic.

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“…The life history of ringed seals has been strongly shaped by sea ice dynamics (Smith and Hammill 1981), as stable land-fast ice is their preferred breeding habitat over pack ice (Smith and Stirling 1975). Ringed seals are trophic omnivorous consumers (Weslawski et al 1994;Dehn et al 2007;Labansen et al 2007;Thiemann et al 2007) that have been reported to undergo an ontogenetic shift in diet from invertebrates to fish (Bradstreet and Cross 1982;Holst et al 2001;Young et al 2010). Ringed seals consume a wide variety of prey species, from herbivorous and carnivorous invertebrates such as mysid, euphausiid, amphipod, and decapod species to fish such as Arctic cod (Boreogadus saida), capelin (Mallotus villosus), sand lance (Ammodytes sp.…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal variation of an ice-adapted predator’s feeding ecology in a changing Arctic marine ecosystem

et al. 2015

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Spatial and temporal variation can confound interpretations of relationships within and between species in terms of diet composition, niche size, and trophic position (TP). The cause of dietary variation within species is commonly an ontogenetic niche shift, which is a key dynamic influencing community structure. We quantified spatial and temporal variations in ringed seal (Pusa hispida) diet, niche size, and TP during ontogeny across the Arctic-a rapidly changing ecosystem. Stable carbon and nitrogen isotope analysis was performed on 558 liver and 630 muscle samples from ringed seals and on likely prey species from five locations ranging from the High to the Low Arctic. A modest ontogenetic diet shift occurred, with adult ringed seals consuming more forage fish (approximately 80 versus 60 %) and having a higher TP than subadults, which generally decreased with latitude. However, the degree of shift varied spatially, with adults in the High Arctic presenting a more restricted niche size and consuming more Arctic cod (Boreogadus saida) than subadults (87 versus 44 %) and adults at the lowest latitude (29 %). The TPs of adult and subadult ringed seals generally decreased with latitude (4.7-3.3), which was mainly driven by greater complexity in trophic structure within the zooplankton communities. Adult isotopic niche size increased over time, likely due to the recent circumpolar increases in subarctic forage fish distribution and abundance. Given the spatial and temporal variability in ringed seal foraging ecology, ringed seals exhibit dietary plasticity as a species, suggesting adaptability in terms of their diet to climate change.

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Spring diet of ringed seals (Phoca hispida) from northwestern Spitsbergen, Norway

Cited by 67 publications

References 27 publications

The amphipod scavenging guild in two Arctic fjords: seasonal variations, abundance and trophic interactions

The amphipod scavenging guild in two Arctic fjords: seasonal variations, abundance and trophic interactions

Influence of sea ice phenology on the movement ecology of ringed seals across their latitudinal range

Spatial and temporal variation of an ice-adapted predator’s feeding ecology in a changing Arctic marine ecosystem

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