scholarly journals Southern elephant seals from Kerguelen Islands confronted by Antarctic Sea ice. Changes in movements and in diving behaviour

2007 ◽  
Vol 54 (3-4) ◽  
pp. 343-355 ◽  
Author(s):  
Frédéric Bailleul ◽  
Jean-Benoıˆt Charrassin ◽  
Robert Ezraty ◽  
Fanny Girard-Ardhuin ◽  
Clive R. McMahon ◽  
...  
Keyword(s):  
Sea Ice ◽  
Diving Behaviour ◽  
Elephant Seals ◽  
Kerguelen Islands ◽  
Antarctic Sea Ice ◽  
Southern Elephant Seals

scholarly journals Decadal changes in blood δ 13 C values, at-sea distribution, and weaning mass of southern elephant seals from Kerguelen Islands

2020 ◽  
Vol 287 (1933) ◽  
pp. 20201544 ◽  
Author(s):  
Julie Mestre ◽  
Matthieu Authier ◽  
Yves Cherel ◽  
Rob Harcourt ◽  
Clive R. McMahon ◽  
...  
Keyword(s):  
Foraging Strategy ◽  
Significant Shift ◽  
Ecological Change ◽  
Foraging Habitat ◽  
Elephant Seals ◽  
Kerguelen Islands ◽  
Phytoplankton Communities ◽  
Foraging Performance ◽  
Southern Elephant Seals ◽  
Foraging Environment

Changes in the foraging environment and at-sea distribution of southern elephant seals from Kerguelen Islands were investigated over a decade (2004–2018) using tracking, weaning mass, and blood δ 13 C values. Females showed either a sub-Antarctic or an Antarctic foraging strategy, and no significant shift in their at-sea distribution was detected between 2004 and 2017. The proportion of females foraging in sub-Antarctic versus Antarctic habitats did not change over the 2006–2018 period. Pup weaning mass varied according to the foraging habitat of their mothers. The weaning mass of sub-Antarctic foraging mothers' pups decreased by 11.7 kg over the study period, but they were on average 5.8 kg heavier than pups from Antarctic foraging mothers. Pup blood δ 13 C values decreased by 1.1‰ over the study period regardless of their sex and the presumed foraging habitat of their mothers. Together, these results suggest an ecological change is occurring within the Indian sector of the Southern Ocean with possible consequences on the foraging performance of southern elephant seals. We hypothesize that this shift in δ 13 C is related to a change in primary production and/or in the composition of phytoplankton communities, but this requires further multidisciplinary investigations.

scholarly journals Successful foraging zones of southern elephant seals from the Kerguelen Islands in relation to oceanographic conditions

2007 ◽  
Vol 362 (1487) ◽  
pp. 2169-2181 ◽  
Author(s):  
Frédéric Bailleul ◽  
Jean-Benoît Charrassin ◽  
Pascal Monestiez ◽  
Fabien Roquet ◽  
Martin Biuw ◽  
...  
Keyword(s):  
Body Condition ◽  
Large Scale ◽  
Foraging Activity ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Kerguelen Islands ◽  
Southern Elephant Seals ◽  
Antarctic Continent ◽  
The Antarctic ◽  
Oceanographic Conditions

Southern elephant seals, Mirounga leonina , undertake large-scale oceanic movements to access favourable foraging areas. Successful foraging areas of elephant seals from the Kerguelen Islands are investigated here in relation to oceanographic parameters. Movements and diving activity of the seals as well as oceanographic data were collected through a new generation of satellite relayed devices measuring and transmitting locations, pressure, temperature and salinity. For the first time, we have associated foraging behaviour, determined by high increased sinuosity in tracks, and dive density (i.e. number of dives performed per kilometre covered), and changes in body condition, determined by variations in drift rate obtained from drift dives, to identify the oceanographic conditions of successful foraging zones for this species. Two main sectors, one close to the Antarctic continent and the other along the Polar Front (PF), where both foraging activity and body condition increase, seem to be of particular interest for the seals. Within these regions, some seals tended to focus their foraging activity on zones with particular temperature signatures. Along the Antarctic continent, some seals targeted colder waters on the sea bottom during benthic dives, while at the PF the favourable zones tended to be warmer. The possible negative effect of colder waters in Antarctic on the swimming performances of potential fish or squid prey could explain the behaviour of elephant seals in these zones, while warmer waters within the PF could correspond to the optimal conditions for potential myctophid prey of elephant seals.

Foraging strategies of southern elephant seals (Mirounga leonina) in relation to frontal zones and water masses

2001 ◽  
Vol 13 (4) ◽  
pp. 371-379 ◽  
Author(s):  
Iain Field ◽  
Mark Hindell ◽  
David Slip ◽  
Kelvin Michael
Keyword(s):  
Dive Depth ◽  
Polar Front ◽  
Water Masses ◽  
Diving Behaviour ◽  
Water Bodies ◽  
Foraging Strategies ◽  
Mirounga Leonina ◽  
Mode Water ◽  
Elephant Seals ◽  
Southern Elephant Seals

Geolocating-time-depth-temperature-recorders (GLTDTR) provided a continuous record of diving behaviour in relation to water temperature for ten female southern elephant seals from Macquarie Island during their post-breeding trips to sea. Four water bodies were determined from depth/temperature profiles recorded by the GLTDTRs. These water bodies corresponded to Sub-Antarctic Mode Water (SAMW), Polar Front Zone Water (PFZW), Polar Front Water (PFW) and Antarctic Water Masses (AWM). Thermal structures within these water bodies did not influence seal diving behaviour. Overall mean dive depth, nocturnal dive depths, diurnal dive depths and dive duration were similar in all areas. However, individuals did change behaviour as they moved between different water bodies. Seals also used different water bodies in the two different years of the study. We suggest that variations in foraging behaviour among seals are a result of prey distribution associated with local oceanographic conditions, but also reflect important individual foraging strategies within thermal zones.

Shift in foraging grounds and diet broadening during ontogeny in southern elephant seals from Kerguelen Islands

2012 ◽  
Vol 160 (4) ◽  
pp. 977-986 ◽  
Author(s):  
Adrien Chaigne ◽  
Matthieu Authier ◽  
Pierre Richard ◽  
Yves Cherel ◽  
Christophe Guinet
Keyword(s):  
Elephant Seals ◽  
Kerguelen Islands ◽  
Southern Elephant Seals

scholarly journals Movement responses to environment: fast inference of variation among southern elephant seals with a mixed effects model

2018 ◽  
Author(s):  
I. D. Jonsen ◽  
C. R. McMahon ◽  
T. A. Patterson ◽  
M. Auger-Méthé ◽  
R. Harcourt ◽  
...  
Keyword(s):  
Sea Ice ◽  
Movement Patterns ◽  
Elephant Seal ◽  
Mixed Effects ◽  
Foraging Strategies ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Movement Model ◽  
Elephant Seals ◽  
Southern Elephant Seals

AbstractLike many species, movement patterns of southern elephant seals (Mirounga leonina) are being influenced by long-term environmental change. These seals migrate up to 4000 km from their breeding colonies, foraging for months in a variety of Southern Ocean habitats. Understanding how movement patterns vary with environmental features and how these relationships differ among individuals employing different foraging strategies can provide insight into foraging performance at a population level. We apply new fast-estimation tools to fit mixed effects within a random walk movement model, rapidly inferring among-individual variability in southern elephant seal environment-movement relationships. We found that seals making foraging trips to the sea-ice on or near the Antarctic continental shelf consistently reduced speed and directionality (move persistence) with increasing sea ice coverage and had variable responses to chlorophyll a concentration, whereas seals that foraged pelagically reduced move persistence in regions where circumpolar deep water shoaled. Given future climate scenarios, pelagic foragers may encounter more productive habitat but sea-ice foragers may see reduced habitat availability. Our approach is scalable to large telemetry data sets and allows flexible combinations of mixed effects to be evaluated via model selection, thereby illuminating the ecological context of animal movements that underlie habitat use.

scholarly journals Inter-population differences in diving behaviour of adult male southern elephant seals (Mirounga leonina)

Polar Biology ◽  
2012 ◽  
Vol 35 (11) ◽  
pp. 1759-1766 ◽  
Author(s):  
B. S. James ◽  
T. McIntyre ◽  
C. A. Tosh ◽  
H. Bornemann ◽  
J. Plötz ◽  
...  
Keyword(s):  
Adult Male ◽  
Diving Behaviour ◽  
Population Differences ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Southern Elephant Seals
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