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.

Movements of southern elephant seals

1996 ◽  
Vol 74 (8) ◽  
pp. 1485-1496 ◽  
Author(s):  
B. J. McConnell ◽  
M. A. Fedak
Keyword(s):  
Southern Ocean ◽  
Continental Shelf ◽  
Antarctic Peninsula ◽  
Average Rate ◽  
Stationary Phases ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
South Georgia ◽  
Southern Elephant Seals ◽  
The Antarctic

Twelve southern elephant seals (Mirounga leonina) were tracked for an average of 119 days as they left their breeding or moulting beaches on the island of South Georgia between 1990 and 1994. Females travelled either eastward up to 3000 km away to the open Southern Ocean or to the continental shelf on or near the Antarctic Peninsula. Males either stayed close to South Georgia or used South Georgia as a base for shorter trips. The females all left South Georgia in a directed manner at an average rate of 79.4 km/day over at least the first 15 days. Thereafter travel was interrupted by bouts of slower travel or stationary phases. The latter were localized at sites on the continental shelf or along its edge. Three seals that were tracked over more than one season repeated their outward direction of travel and used some of the same sites in subsequent years. The magnitude of the movements makes most of the Southern Ocean potentially available to elephant seals.

Migrations and foraging of juvenile southern elephant seals from Macquarie Island within CCAMLR managed areas

2002 ◽  
Vol 14 (2) ◽  
pp. 134-145 ◽  
Author(s):  
John van den Hoff ◽  
Harry R. Burton ◽  
Mark A. Hindell ◽  
Michael D. Sumner ◽  
Clive R. McMahon
Keyword(s):  
Foraging Ecology ◽  
Polar Front ◽  
Commercial Fishing ◽  
Antarctic Polar Front ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Macquarie Island ◽  
Location Data ◽  
Southern Elephant Seals ◽  
The Antarctic

Twenty-three juvenile (8–14 months of age) southern elephant seals (Mirounga leonina L.) from Macquarie Island were tracked during 1993 and 1995. Migratory tracks and ocean areas with concentrated activity, presumed to be foraging grounds, were established from location data gathered by attached geolocation-time depth recorders. The seals ranged widely (811–3258 km) and foraging activity centred on oceanographic frontal systems, especially the Antarctic Polar Front and bathymetric features such as the Campbell Plateau region. The seals spent 58.6% of their sea time within managed fishery areas while the remainder was spent on the high seas, an area of unregulated fishing. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) areas 58.4.1, 88.2 and especially 88.1 were important and distant foraging areas for these juvenile elephant seals. From fisheries records, diet and the foraging ecology studies of the seals there appears to be little, if any, overlap or conflict between the seals and commercial fishing operations within the regulated commercial areas. However, attention is drawn to the possibility of future interactions if Southern Ocean fisheries expand or new ones commence.

scholarly journals Local weather and body condition influence habitat use and movements on land of molting female southern elephant seals (Mirounga leonina )

2018 ◽  
Vol 8 (12) ◽  
pp. 6081-6090 ◽  
Author(s):  
Laureline L. Chaise ◽  
Iris Prinet ◽  
Camille Toscani ◽  
Susan L. Gallon ◽  
William Paterson ◽  
...  
Keyword(s):  
Habitat Use ◽  
Body Condition ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
Local Weather

A comparison of techniques used to estimate body condition of southern elephant seals (Mirounga leonina)

2001 ◽  
Vol 28 (6) ◽  
pp. 581 ◽  
Author(s):  
Megan Tierney ◽  
Mark Hindell ◽  
Mary-Anne Lea ◽  
Dominic Tollit
Keyword(s):  
Body Condition ◽  
Tritiated Water ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
Comparison Of Techniques ◽  
Total Body ◽  
Condition Indices

The total body water (TBW) and body condition of 86 female southern elephant seals was estimated from tritiated water (HTO) dilution space analysis. HTO blood samples were analysed using two distillation methods (direct serum counts and evaporative freeze capture) that yielded significantly different estimates. Evaporative freeze capture is recommended for use because it is faster, cheaper, and provides a more precise TBW estimate of dilution space. Estimates of TBW were then compared with those derived from bioelectrical impedance analysis (BIA) and morphometric models. There were significant, positive relationships between TBW and BIA variables, but the level of accuracy was inadequate for BIA to be more useful than the other methods trialled. Morphometric models accurately estimated TBW (kg). Models developed from surface area (SA) (TBW = [SA * 82.58] – 86.94) and from a combination of mass (M), length (L), and girth (G) (TBW = [(M * 0.72) + (L * 5.49) + (G * 134.94) + 164.36)] provided the most accurate TBW estimates. In contrast, condition indices did not give accurate or reliable estimates of relative body condition.

Foraging areas of southern elephant seals, Mirounga leonina, as inferred from water temperature data

1991 ◽  
Vol 42 (2) ◽  
pp. 115 ◽  
Author(s):  
MA Hindell ◽  
HR Burton ◽  
DJ Slip
Keyword(s):  
Continental Shelf ◽  
Polar Front ◽  
Antarctic Polar Front ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Antarctic Continental Shelf ◽  
Southern Elephant Seals ◽  
Water Temperature Data ◽  
The Antarctic ◽  
Temperature Depth

Fourteen time-depth-temperature recorders were recovered from adult southern elephant seals (Mirounga leonina) returning to Macquarie Island to breed or moult. The resulting temperature/depth profiles indicated that all four males spent most of their time in waters lying over the Antarctic Continental Shelf, whereas only one of the ten females spent any time there. Five of the females foraged just off the Antarctic Continental Shelf. and the other five remained near the Antarctic Polar Front.

scholarly journals Cephalopoda as prey of juvenile Southern elephant seals at Isla 25 de Mayo/King George, South Shetland Islands

2015 ◽  
Vol 105 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Luciana Burdman ◽  
Gustavo A. Daneri ◽  
Javier Negrete ◽  
Jorge A. Mennucci ◽  
Maria E. I. Marquez
Keyword(s):  
Southern Oscillation ◽  
Feeding Habits ◽  
South Shetland Islands ◽  
Antarctic Polar Front ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Shetland Islands ◽  
Numerical Abundance ◽  
Southern Elephant Seals ◽  
The Antarctic

The aim of the present study was to enhance the knowledge of the feeding habits of the juvenile component of the population of Southern elephant seals [Mirounga leonina (Linnaeus, 1758)] from Isla 25 de Mayo, South Shetland Islands, age class whose diet information is scarce. A total of 60 individuals were stomach lavaged in the spring - summer seasons of three consecutive years (2003, 2004 and 2005) of which 53.3 % (n = 32) presented food remnants. The Antarctic glacial squid Psychroteuthis glacialis Thiele, 1921 was the dominant prey taxon in terms of frequency of occurrence (68.7%), numerical abundance (60.1%) and biomass (51.5%), contributing 84.1% to the total relative importance index. Other squid prey species of importance were Slosarczykovia circumantartica Lipinski, 2001 in terms of occurrence (37.5%) and numerical abundance (14%) and Moroteuthis knipovitchi Filippova, 1972 in terms of biomass (16%). All identified cephalopod prey taxa are distributed south of the Antarctic Polar Front, except for the squid Martialia hyadesi Rochebrune & Mabille, 1889 which has a circumpolar distribution associated to the Polar Frontal Zone. No significant differences in the sizes of P. glacialis preyed upon by elephant seals were found between sexes and years. However, significant interannual differences were found in the taxonomical composition of their diet. This would be associated with temporal changes in food availability at the foraging areas of seals, which in turn may have been influenced by changes in oceanographic conditions as a result of the El Niño Southern Oscillation (ENSO) phenomenon that occurred during part of the study period. Furthermore, a differential response of males and females to this temporal variation was observed, with the former being also associated to a predation on octopods. This would suggest a sexual segregation in foraging habits of this species from the early stages of its life cycle.

Cephalopod prey of the southern elephant seal, Mirounga leonina L.

1992 ◽  
Vol 70 (5) ◽  
pp. 1007-1015 ◽  
Author(s):  
P. G. Rodhouse ◽  
T. R. Arnbom ◽  
M. A. Fedak ◽  
J. Yeatman ◽  
A. W. A. Murray
Keyword(s):  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Antarctic Polar Front ◽  
Mirounga Leonina ◽  
Important Species ◽  
Elephant Seals ◽  
South Georgia ◽  
Cephalopod Species ◽  
Southern Elephant Seals ◽  
The Antarctic

In the austral summers of 1986 and 1988–1989, 51 southern elephant seals (Mirounga leonina) at Husvik, South Georgia (54°10′S; 36°43′W), were stomach lavaged after chemical immobilization. Only cephalopod remains were retrieved, including 1070 lower beaks that were identified and measured. In total these were estimated to represent a wet weight of 187.8 kg. Fourteen species of squid from 11 families and 2 species of octopod from 1 family were present. The most important species overall were the squids Psychroteuthis glacialis in terms of numerical abundance (33.7%) and Moroteuthis knipovitchi in terms of estimated biomass (31.2%). The remaining biomass was mainly comprised of the five large muscular squids, Kondakovia longimana (24.0%), P. glacialis (15.4%), Martialia hyadesi (11.2%), Alluroteuthis antarcticus (10.8%), and Gonatus antarcticus (3.6%). Larger seals of both sexes fed on a wider variety of cephalopod species than smaller seals, with large males taking the greatest diversity. Between the two summers of the study there were some changes in the relative importance of the various cephalopod species consumed; in particular, in 1988–1989 M. knipovitchi and M. hyadesi were less important and P. glacialis was more important. The taxa and size of cephalopods taken by southern elephant seals at South Georgia are almost identical to those taken by the grey-headed albatross (Diomedea chrysostoma), but the relative proportions are quite different. The biogeography of the cephalopods eaten suggests that southern elephant seals sampled at South Georgia do not forage to the north of the Antarctic Polar Front but probably travel southwards towards the Antarctic continent or Peninsula.

The Diving Behavior of Adult Male and Female Southern Elephant Seals, Mirounga-Leonina (Pinnipedia, Phocidae)

1991 ◽  
Vol 39 (5) ◽  
pp. 595 ◽  
Author(s):  
MA Hindell ◽  
DJ Slip ◽  
HR Burton
Keyword(s):  
Geographic Location ◽  
Temperature Data ◽  
Diving Behavior ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Antarctic Continental Shelf ◽  
Southern Elephant Seals ◽  
Water Temperature Data ◽  
Time Of Year ◽  
The Antarctic

Over 50 000 individual dive records collected by time-depth recorders were analysed with respect to sex of the seal, time of year and the approximate geographic location of the dive. Six distinct dive types were described on the basis of parameters such as the amount of time spent at the maximum depth of the dive, the rate of ascent and descent, and the general form of the dive profile. These dive types were 'rest' dives, 'travel' dives, 'surface' dives, 'general non-foraging' dives, 'pelagic foraging' dives and 'benthic foraging' dives. The seals spent 90% of their time at sea submerged. Less than 2% of the time was spent on the surface in intervals of more than 10 min. A further 20-30% of the time was spent on the various non-foraging types of dives. Most females performed only 'pelagic foraging' dives, while males performed both 'pelagic' and 'benthic foraging' dives. All the 'benthic foraging' dives occurred in Area 3 (defined by water-temperature data as lying over the Antarctic Continental Shelf) and were 400-500 m deep. 'Pelagic foraging' dives occurred in all three foraging areas and ranged in depth from 200 to 1100 m. These types of dives also exhibited marked diurnal variations in depth, unlike 'benthic foraging' dives. The seals spent 10-20 min at the bottom of each 'foraging' dive, where they generally displayed a series of small changes in depth (wiggles). The size of these 'wiggles' tended to be larger in 'pelagic foraging' dives than in 'benthic foraging' dives. The diving behaviour of southern elephant seals is related to the possible prey they exploit in the Southern Ocean.

Serological screening for Brucella spp. and Leptospira spp. antibodies in southern elephant seals Mirounga leonina from Elephant Island, Antarctica, in 2003 and 2004

2020 ◽  
Vol 142 ◽  
pp. 161-170
Author(s):  
AM Sánchez-Sarmiento ◽  
V Ruoppolo ◽  
MMC Muelbert ◽  
JS Ferreira Neto ◽  
JL Catão-Dias
Keyword(s):  
Austral Summer ◽  
Agglutination Test ◽  
South Shetland Islands ◽  
Climate Change Scenarios ◽  
Mirounga Leonina ◽  
Serological Screening ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
Monitoring And Surveillance ◽  
Elephant Island

Brucella spp. and Leptospira spp. antibodies were surveyed in 35 southern elephant seals (SESs) Mirounga leonina at Elephant Island (South Shetland Islands), western Antarctic peninsula, in the Austral summer of 2003 and 2004. The rose Bengal test and a commercial competitive ELISA (c-ELISA) were used to detect Brucella spp. exposure, and the microscopic agglutination test (MAT) with 22 live serovars was used to determine anti-Leptospira spp. antibodies. We found evidence of Brucella spp. exposure in 3 of 35 (8.6%) SESs tested via the c-ELISA displaying high percentage inhibition (PI), similar to other studies in pinnipeds in which Brucella spp. antibodies have been determined. Two of the 3 positives were pups (PI = 70.4 and 86.6%), while the third was an adult female (PI = 48.8%). The 3 c-ELISA positive SESs were additionally tested via the serum agglutination test but were found to be negative. All individuals were negative for antibodies against 22 Leptospira spp. serovars by MAT. These results contribute to the knowledge and monitoring of zoonotic pathogens with epizootic potential in Southern Ocean pinnipeds. Given the potential impact that pathogens may have on the abundance of wild (sometimes threatened and endangered) populations, constant monitoring and surveillance are required to prevent pathogen spread, particularly under forecast climate change scenarios.

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