Weddell seal behaviour during an exceptional oceanographic event in the Filchner-Ronne Ice Shelf in 2017

Labrousse, Sara; Ryan, Svenja; Roquet, Fabien; Picard, Baptiste; McMahon, Clive R.; Harcourt, Robert; Hindell, Mark A.; Goff, Hervé Le; Lourenço, Antonio; David, Y; Sallée, Jean‐Baptiste; Charrassin, Jean‐Benoît

doi:10.1017/s0954102021000092

Cited by 7 publications

(5 citation statements)

References 40 publications

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“…Our results differ from studies of Weddell seal distributions in the Weddell Sea (Boehme et al, 2016;Nachtsheim et al, 2019;Photopoulou et al, 2020;Labrousse et al, 2021), where tracked individuals showed diverse and wide-ranging movements including moving off the Antarctic continental shelf. In those studies, seals were often captured from ships some distance from the coast and later in the winter.…”

Section: Individual Variabilitycontrasting

confidence: 99%

“…Hunting dives at both locations were pelagic, concentrated in areas of high ice concentration, over areas of relatively complex bathymetry and favouring water masses such as Antarctic Surface Water and mCDW (Heerah et al, 2013(Heerah et al, , 2016. However, other studies from the Ross Sea (Testa, 1994) and the Weddell Sea (Nachtsheim et al, 2019;Photopoulou et al, 2020;Labrousse et al, 2021) reported dispersal of several hundred kilometres, albeit for the most part staying close to or over the continental shelf.…”

Section: Introductionmentioning

confidence: 80%

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Regional Variation in Winter Foraging Strategies by Weddell Seals in Eastern Antarctica and the Ross Sea

et al. 2021

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The relative importance of intrinsic and extrinsic determinants of animal foraging is often difficult to quantify. The most southerly breeding mammal, the Weddell seal, remains in the Antarctic pack-ice year-round. We compared Weddell seals tagged at three geographically and hydrographically distinct locations in East Antarctica (Prydz Bay, Terre Adélie, and the Ross Sea) to quantify the role of individual variability and habitat structure in winter foraging behaviour. Most Weddell seals remained in relatively small areas close to the coast throughout the winter, but some dispersed widely. Individual utilisation distributions (UDi, a measure of the total area used by an individual seal) ranged from 125 to 20,825 km2. This variability was not due to size or sex but may be due to other intrinsic states for example reproductive condition or personality. The type of foraging (benthic vs. pelagic) varied from 56.6 ± 14.9% benthic dives in Prydz Bay through 42.1 ± 9.4% Terre Adélie to only 25.1 ± 8.7% in the Ross Sea reflecting regional hydrographic structure. The probability of benthic diving was less likely the deeper the ocean. Ocean topography was also influential at the population level; seals from Terre Adélie, with its relatively narrow continental shelf, had a core (50%) UD of only 200 km2, considerably smaller than the Ross Sea (1650 km2) and Prydz Bay (1700 km2). Sea ice concentration had little influence on the time the seals spent in shallow coastal waters, but in deeper offshore water they used areas of higher ice concentration. Marine Protected Areas (MPAs) in the Ross Sea encompass all the observed Weddell seal habitat, and future MPAs that include the Antarctic continental shelf are likely to effectively protect key Weddell seal habitat.

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Section: Individual Variabilitycontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 80%

Regional Variation in Winter Foraging Strategies by Weddell Seals in Eastern Antarctica and the Ross Sea

et al. 2021

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“…The flow of mWDW during austral summer through the Small Trough is further supported by current and temperature measurements taken over one year by the mooring P5 located in the Small Trough. Also, consistent with this flow, Labrousse et al (2021) described the presence of a large pool of mWDW in 2017 over the entire continental shelf east of the Filchner Trough, found as far east as 28 • W, although their observations were slightly later in the year, in June and July. This collection of observations thus suggests that both the northeastern corner of the Filchner Trough and the Small Trough support a southward mWDW pathway in summer.…”

Section: Discussionsupporting

confidence: 60%

“…Ship-based observations are only possible during summer and are mostly concentrated in regions lightly covered by sea-ice during this period. Marine mammal observations depend on seal behaviour (Labrousse et al, 2021), so cannot be targeted toward specific currents or water-masses; also, they do not usually cover the entire water column and have larger measurement and positioning uncertainties than ship-based observations (Siegelman et al, 2019). Mooring observations over the continental shelf (e.g.…”

Section: Introductionmentioning

confidence: 99%

Subsurface floats in the Filchner Trough provide first direct under-ice tracks of eddies and circulation on shelf

Sallée,

Vignes,

Minière

et al. 2023

Preprint

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Abstract. Bottom water formation in the Weddell Sea and mass loss from the Filchner-Ronne Ice Shelf are tightly linked by the supply of Warm Deep Water to the continental shelf. Heavy sea ice cover and icebergs restrict ship access and upper ocean measurements by moorings, compelling us to try new sampling methods. We present results from the first dedicated under-sea-ice float experiment tracking circulation on the continental shelf between the Brunt Ice Shelf and Filchner Ice Shelf. Seven Apex profiling floats were deployed in 2017 at three different locations, targeting the sources of modified Warm Deep Water (mWDW) inflow and Ice Shelf Water (ISW) circulation in the Filchner Trough. The floats capture a warm mWDW regime with southward inflow over the eastern continental shelf and a cold ISW regime with a recirculation of ISW in the Filchner Trough throughout the four years of observations. The mWDW flowing onto the continental shelf follows two pathways: the eastern flank of the Filchner Trough and via a Small Trough on the shallow shelf farther east. In the present circulation regime, this warm water is blocked from reaching the ice shelf cavity due to the presence of the thick ISW layer inside the Filchner Trough. The floats' trajectories and hydrography reveal the dynamically active front, flow reversal, and eddy generation between these two water masses along the eastern flank of the Filchner Trough.

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“…Southern elephant seals also provide unprecedented sampling of coastal polynyas and regions of bottom water formation and therefore key observations on the dynamics of ocean ventilation (Ohshima et al, 2013(Ohshima et al, , 2016Malpress et al, 2017;Labrousse et al, 2018). The ice-obligated Weddell seal (Leptonychotes weddellii) is also a deep diver that often dives to the ocean floor along the Antarctic continental shelf (Piñones et al, 2019;Labrousse et al, 2021). However, individuals generally stay within a 100 km of the tagging location, providing detailed local sampling but limiting the breadth of observations compared to elephant seals (Heerah et al, 2016;Nachtsheim et al, 2019;Photopoulou et al, 2020).…”

Section: Speciesmentioning

confidence: 99%

Animal Borne Ocean Sensors – AniBOS – An Essential Component of the Global Ocean Observing System

et al. 2021

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Marine animals equipped with biological and physical electronic sensors have produced long-term data streams on key marine environmental variables, hydrography, animal behavior and ecology. These data are an essential component of the Global Ocean Observing System (GOOS). The Animal Borne Ocean Sensors (AniBOS) network aims to coordinate the long-term collection and delivery of marine data streams, providing a complementary capability to other GOOS networks that monitor Essential Ocean Variables (EOVs), essential climate variables (ECVs) and essential biodiversity variables (EBVs). AniBOS augments observations of temperature and salinity within the upper ocean, in areas that are under-sampled, providing information that is urgently needed for an improved understanding of climate and ocean variability and for forecasting. Additionally, measurements of chlorophyll fluorescence and dissolved oxygen concentrations are emerging. The observations AniBOS provides are used widely across the research, modeling and operational oceanographic communities. High latitude, shallow coastal shelves and tropical seas have historically been sampled poorly with traditional observing platforms for many reasons including sea ice presence, limited satellite coverage and logistical costs. Animal-borne sensors are helping to fill that gap by collecting and transmitting in near real time an average of 500 temperature-salinity-depth profiles per animal annually and, when instruments are recovered (∼30% of instruments deployed annually, n = 103 ± 34), up to 1,000 profiles per month in these regions. Increased observations from under-sampled regions greatly improve the accuracy and confidence in estimates of ocean state and improve studies of climate variability by delivering data that refine climate prediction estimates at regional and global scales. The GOOS Observations Coordination Group (OCG) reviews, advises on and coordinates activities across the global ocean observing networks to strengthen the effective implementation of the system. AniBOS was formally recognized in 2020 as a GOOS network. This improves our ability to observe the ocean’s structure and animals that live in them more comprehensively, concomitantly improving our understanding of global ocean and climate processes for societal benefit consistent with the UN Sustainability Goals 13 and 14: Climate and Life below Water. Working within the GOOS OCG framework ensures that AniBOS is an essential component of an integrated Global Ocean Observing System.

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Weddell seal behaviour during an exceptional oceanographic event in the Filchner-Ronne Ice Shelf in 2017

Cited by 7 publications

References 40 publications

Regional Variation in Winter Foraging Strategies by Weddell Seals in Eastern Antarctica and the Ross Sea

Regional Variation in Winter Foraging Strategies by Weddell Seals in Eastern Antarctica and the Ross Sea

Subsurface floats in the Filchner Trough provide first direct under-ice tracks of eddies and circulation on shelf

Animal Borne Ocean Sensors – AniBOS – An Essential Component of the Global Ocean Observing System

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