Ultrasonic Measurement of Blubber Thickness of the Southern Elephant Seal, Mirounga-Leonina (Linn)

1987 ◽  
Vol 35 (3) ◽  
pp. 207 ◽  
Author(s):  
NJ Gales ◽  
HR Burton
Keyword(s):  
Subcutaneous Fat ◽  
Elephant Seal ◽  
Ultrasonic Measurement ◽  
Southern Elephant Seal ◽  
Future Research ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Non Invasive ◽  
Fat Reserves ◽  
Southern Elephant Seals

Ultrasound measurements of subcutaneous fat at 18 body sites on each of 23 southern elephant seals Mirounga leonina (Linn.), together with circumference and length measurements, were used to estimate the total subcutaneous blubber weight on each animal. Twelve cows (including animals that were pregnant and others at early, mid-, late and post-lactation), 10 males and one male pup were anaesthetised for these measurements, made at Heard I. (53�01'S.,73�23'E.) on various dates in October and November 1985. Comparison of the estimates of blubber weight from cows at various stages of lactation allowed a mean blubber loss of 62.8 kg per cow per lactation to be calculated. It is suggested that measuring variations in the subcutaneous fat reserves of cows coming ashore to pup at Heard I. may be one relevant approach in any future research that attempts to explain the 60% drop in pup production at that island between 1949 and 1985. The use of ultrasound to estimate the subcutaneous fat reserves of seals was shown to be a safe, non-invasive and logistically practical technique.

Physiological implications of continuous, prolonged, and deep dives of the southern elephant seal (Mirounga leonina)

1992 ◽  
Vol 70 (2) ◽  
pp. 370-379 ◽  
Author(s):  
Mark A. Hindell ◽  
David J. Slip ◽  
Harry R. Burton ◽  
Michael M. Bryden
Keyword(s):  
Resting Metabolic Rate ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Adult Males ◽  
Mirounga Leonina ◽  
Physiological Mechanisms ◽  
Elephant Seals ◽  
Aerobic Dive Limit ◽  
Southern Elephant Seals ◽  
Extended Surface

The diving behaviour of 14 adult southern elephant seals was investigated using time depth recorders. Each of the seals performed some dives that were longer than its theoretical aerobic dive limit. Forty-four percent of all dives made by post-moult females exceeded the calculated limit compared with 7% of those made by postbreeding females and less than 1% of those made by adult males. The extended dives displayed characteristics that suggested that they were predominantly foraging dives, although some were apparently rest dives. Dives longer than the calculated aerobic limits often occurred in bouts; the longest consisted of 63 consecutive dives and lasted 2 days. Postmoult females performed longer bouts of extended dives than postbreeding females. Extended surface periods (longer than 30 min) were not related to the occurrence of extended dives or bouts of extended dives. The possible physiological mechanisms that permit such prolonged continuous dives are discussed. Southern elephant seals may increase the aerobic capacity of dives by lowering their metabolism to approximately 40% of the resting metabolic rate on long dives. There is substantial interseal variability in the methods used to cope with long dives. Some animals appear to use physiological strategies that allow them to prolong the time available to them at the bottom of a dive, while others use alternative strategies that may limit the time available at the bottom of their dives.

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.

Cephalopod diet of the southern elephant seal, Mirounga leonina, at King George Island, South Shetland Islands

2000 ◽  
Vol 12 (1) ◽  
pp. 16-19 ◽  
Author(s):  
G.A. Daneri ◽  
A.R. Carlini ◽  
P.G.K. Rodhouse
Keyword(s):  
Stomach Contents ◽  
Elephant Seal ◽  
South Shetland Islands ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
King George Island ◽  
Elephant Seals ◽  
Shetland Islands ◽  
Important Prey ◽  
Southern Elephant Seals

In the summer of 1995/96, 25 southern elephant seals, Mirounga leonina, were stomach lavaged at Stranger Point, King George Island, South Shetland Islands. Cephalopod remains were present in 72% of the individuals sampled (n = 18). Seven species of squid and three of octopus were identified. The squid Psychroteuthis glacialis was the most important prey in terms of numbers (77%), biomass (80.8%) and frequency of occurrence (94.4%). Next in importance in terms of mass was the squid Alluroteuthis antarcticus (7.8%) in the diet of females and the octopodid Pareledone ?charcoti in the diet of males (13.2%). Females preyed on a wider variety of squid taxa than males (7 vs 3) but octopodids occurred only in stomach contents from males. The predominance of P. glacialis in the prey of the South Shetland Islands elephant seals can be explained by the southerly location of the foraging areas of this population compared to South Georgia, Heard and Macquarie islands, where the diet of southern elephant seals has previously been analysed. Psychroteuthis glacialis is the predominant squid in waters close to the Antarctic continent.

Age in relation to Breeding to Status of the Male Southern Elephant Seal, Mirounga leonina (L.), at Macquarie Island

1981 ◽  
Vol 8 (2) ◽  
pp. 327 ◽  
Author(s):  
E Jones
Keyword(s):  
Elephant Seal ◽  
Progressive Increase ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Macquarie Island ◽  
Southern Elephant Seals ◽  
Definition Of ◽  
Breeding Seasons ◽  
Breeding Status

Records of the breeding status of known-age male southern elephant seals at Macquarie I. were kept during five breeding seasons between 1969 and 1976. The seven status categories used were: beachmaster, secure assistant, medium harem owner, insecure assistant, small harem owner, attending bachelor, avoiding bachelor. There was a progressive increase in breeding status with age; none younger than 10-y-old bred: 16% of 10-y-olds, 30% of 11-y-olds and 55% of 12-y-olds did so; none younger than 12-y-old attained secure assistant status. At the earliest, beachmaster status may be attained at 14 y old, but no beachmasters of known age were recorded. Due to mortality and competition, most males do not breed and few breed for more than two seasons. Problems associated with the precise definition of status categories are discussed.

scholarly journals Dispersal of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: Combining population genetics and tracking data

2021 ◽  
Author(s):  
Michelle Chua ◽  
Simon Ho ◽  
Clive McMahon ◽  
Ian Jonsen ◽  
Mark de Bruyn
Keyword(s):  
Genetic Diversity ◽  
Marine Environment ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Tracking Data ◽  
Mirounga Leonina ◽  
Long Distance ◽  
Elephant Seals ◽  
Macquarie Island ◽  
Southern Elephant Seals

Marine animals such as the southern elephant seal (Mirounga leonina) rely on a productive marine environment and are vulnerable to oceanic changes that can affect their reproduction and survival rates. Davis Base, Antarctica, acts as a moulting site for southern elephant seals that forage in Prydz Bay, but the genetic diversity and natal source populations of these seals has not been characterized. Determining the genetic diversity of moulting populations like this one provides essential information on seal dispersal, inter-population mixing, and foraging behaviours. In this study, we combined genetic and animal tracking data on these moulting seals to identify levels of genetic diversity, natal source population, and movement behaviours during foraging and haul-out periods. Using mitochondrial sequence data, we identified two major breeding lineages of seals at Davis Base. We found that the majority of the seals originated from breeding stocks within the South Atlantic Ocean and South Indian Ocean. One seal was grouped with the Macquarie Island breeding stock (South Pacific Ocean). The Macquarie Island population, unlike the other two stocks, is decreasing in size. Tracking data revealed long-distance foraging activity of the Macquarie Island seal around Crozet Islands. We speculate that changes to the Antarctic marine environment have resulted in a shift in foraging and dispersal strategies, which subsequently affects seal population growth rates. These findings have implications for conservation management plans aimed at improving the population status of the southern elephant seal.

scholarly journals Sex-specific foraging strategies and resource partitioning in the southern elephant seal ( Mirounga leonina )

2006 ◽  
Vol 273 (1603) ◽  
pp. 2901-2907 ◽  
Author(s):  
Rebecca Lewis ◽  
Tamsin C O'Connell ◽  
Mirtha Lewis ◽  
Claudio Campagna ◽  
A. Rus Hoelzel
Keyword(s):  
Sampling Strategy ◽  
Elephant Seal ◽  
Foraging Strategies ◽  
Southern Elephant Seal ◽  
South American ◽  
Prey Choice ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Sea Lions ◽  
Southern Elephant Seals

The evolution of resource specializations is poorly understood, especially in marine systems. The southern elephant seal ( Mirounga leonina ) is the largest of the phocid seals, sexually dimorphic, and thought to prey predominantly on fish and squid. We collected vibrissae from male and female southern elephant seals, and assessed stable C and N isotope ratios along the length of the vibrissae. Given that whiskers grow slowly, this sampling strategy reflects any variation in feeding behaviour over a period of time. We found that isotopic variation among females was relatively small, and that the apparent prey choice and trophic level of females was different from that for males. Further, males showed a very broad range of trophic/prey choice positions, grouped into several clusters, and this included isotopic values too low to match a broad range of potential fish and cephalopod prey tested. One of these clusters overlapped with data for South American sea lions ( Otaria flavescens ), which were measured for comparison. Both male southern elephant seals and southern sea lions forage over the continental shelf, providing the potential for competition. We discuss the possibility that individual southern elephant seals are pursuing specialist foraging strategies to avoid competition, both with one another, and with the South American sea lions that breed nearby.

Tagging Elephant Seals for life-history studies

Polar Record ◽  
1967 ◽  
Vol 13 (85) ◽  
pp. 443-446 ◽  
Author(s):  
A. B. Dickinson
Keyword(s):  
Subcutaneous Fat ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Breeding Period ◽  
Population Census ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Bull Calves ◽  
Annual Population ◽  
Image Position

South Georgia has been the site of a controlled commercial sealing industry since 1909. The Southern Elephant Seal (Mirounga leonina) is killed for the oil obtained from the processing of the skin and subcutaneous fat, in a manner similar to the processing of whale blubber.The island is divided into four sealing divisions, each with an annual catch quota which is subject to revision if necessary at the completion of each season, depending on information obtained from the average age of the catch, and an annual population census. There are also reserve areas, in which commercial killing is prohibited and which provide controls for comparison between commercially exploited herds and those which are undisturbed. The latter begin to breed an earlier age, reach their peak breeding period earlier and bear a smaller ratio of cow to bull calves than the former. The total kill permissible over the last decade has remained at 6000 adult bull seals over 3·5 m in length. At present, the catch quotas in each division are as follows:

Tag-loss in southern elephant seals, Mirounga leonina, at Marion Island

1997 ◽  
Vol 9 (2) ◽  
pp. 162-167 ◽  
Author(s):  
I.S. Wilkinson ◽  
M.N. Bester
Keyword(s):  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Island Population ◽  
Marion Island ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Tag Loss ◽  
Southern Elephant Seals ◽  
Marking Technique ◽  
Loss Rates

Rates of tag-loss are determined for Dalton Jumbo Rototags applied to the hind flippers of 4343 (2208 males, 2135 females) southern elephant seal (Mirounga leonina) pups at Marion Island over an eight year period from 1983–1990 as part of a demographic study of the species. Loss rates were the lowest recorded to date for this species (range 0.0–9.1%). No significant relationship existed between age and rate of tag-loss, neither was there any sex or year related differences in age-specific tag-loss rates. The low rates of loss highlight the value of tagging as a marking technique, and allow for high levels of confidence in the reliability of the population parameters that are derived from the tagging data collected for the Marion Island population.

Determining Blubber Mass in the Southern Elephant Seal, Mirounga-Leonina, by Ultrasonic and Isotopic Techniques

1992 ◽  
Vol 40 (2) ◽  
pp. 143 ◽  
Author(s):  
DJ Slip ◽  
HR Burton ◽  
NJ Gales
Keyword(s):  
Total Body Water ◽  
Tritiated Water ◽  
Subcutaneous Fat ◽  
Body Water ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
Total Body ◽  
The Relationship

The mass of subcutaneous fat was determined for 14 male southern elephant seals, Mirounga leonina, by a modified version of a previously described ultrasound model (Gales and Burton 1987). The new model took into account fat slumping and was more accurate than the first model. The accuracy of the new technique was assessed by flensing. Total body water was estimated by tritiated-water dilution, and the relationship between total body water and ultrasonically determined total blubber mass was established. Predictive relationships for total blubber mass, and the relationship between total blubber mass and total body fat were determined. This study has demonstrated the applicability of ultrasound and isotope-dilution techniques in determining the fat composition in vivo of southern elephant seals.

scholarly journals Arbovirus of Marine Mammals: a New Alphavirus Isolated from the Elephant Seal Louse, Lepidophthirus macrorhini

2001 ◽  
Vol 75 (9) ◽  
pp. 4103-4109 ◽  
Author(s):  
May La Linn ◽  
Joy Gardner ◽  
David Warrilow ◽  
Grant A. Darnell ◽  
Clive R. McMahon ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Marine Mammals ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Serological Evidence ◽  
Elephant Seals ◽  
Macquarie Island ◽  
Southern Elephant Seals ◽  
Virus Sequence

ABSTRACT A novel alphavirus was isolated from the louse Lepidophthirus macrorhini, collected from southern elephant seals,Mirounga leonina, on Macquarie Island, Australia. The virus displayed classic alphavirus ultrastructure and appeared to be serologically different from known Australasian alphaviruses. Nearly all Macquarie Island elephant seals tested had neutralizing antibodies against the virus, but no virus-associated pathology has been identified. Antarctic Division personnel who have worked extensively with elephant seals showed no serological evidence of exposure to the virus. Sequence analysis illustrated that the southern elephant seal (SES) virus segregates with the Semliki Forest group of Australasian alphaviruses. Phylogenetic analysis of known alphaviruses suggests that alphaviruses might be grouped according to their enzootic vertebrate host class. The SES virus represents the first arbovirus of marine mammals and illustrates that alphaviruses can inhabit Antarctica and that alphaviruses can be transmitted by lice.

Sign in / Sign up

Export Citation Format

Share Document