Participation in the winter haulout by southern elephant seals (Mirounga leonina)

2001 ◽  
Vol 13 (4) ◽  
pp. 380-384 ◽  
Author(s):  
S.P. Kirkman ◽  
M.N. Bester ◽  
P.A. Pistorius ◽  
G.J.G. Hofmeyr ◽  
R. Owen ◽  
...  
Keyword(s):  
First Year ◽  
Marion Island ◽  
Mirounga Leonina ◽  
Mark Recapture ◽  
Elephant Seals ◽  
Immature Male ◽  
Southern Elephant Seals ◽  
Unknown Reason ◽  
First Year Of Life

Southern elephant seals haulout on land to moult, breed and for a third, unknown reason, which we refer to as the winter haulout. We used long-term mark-recapture data to estimate participation levels in the winter haulout by southern elephant seals at Marion Island. There was no evidence that participation levels varied between cohorts or between years. Participation differed between sexes, with males being more likely to haulout in winter, except in the first year of life where participation was equal. Within each sex, both age and reproductive status influenced participation, but age seemed to be the most influential determinant. Generally, immature male individuals hauled out year after year in winter. The results did not allow speculation as to the purpose(s) of the winter haulout.

Growth of Southern Elephant Seals, Mirounga leonina, during their First Foraging Trip

1997 ◽  
Vol 45 (5) ◽  
pp. 447 ◽  
Author(s):  
Cameron M. Bell ◽  
Harry R. Burton ◽  
Mark A. Hindell
Keyword(s):  
Body Composition ◽  
Body Size ◽  
Body Mass ◽  
First Year ◽  
Mirounga Angustirostris ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
First Year Of Life ◽  
Foraging Skills

A longitudinal study of growth of southern elephant seals, Mirounga leonina, during their first foraging trip was undertaken at Macquarie Island. On average, body mass increased by 75% while foraging at sea, with individuals growing at 0.34 ± 0.12 (s.d.) kg day-1 (n = 64), and spending 182 ± 51 days (n = 64) at sea. Relatively smaller changes in body length were recorded during the same period, suggesting that growth was composed primarily of adjustments to body composition, rather than increases in gross body size. This may be in response to the functional demands of pelagic life. Body size established early in life (birth mass and departure mass) positively influenced body mass upon return from the first foraging trip. Growth rate, however, was negatively related to departure mass for females, and this is hypothesised to be related to sex differences in body composition, as well as intrasex differences in foraging skills, diving ability and food- conversion efficiency. Despite this, there was no detectable age-specific sexual dimorphism in the first year of life. Animals that were at sea longer tended to return in better body condition. Interspecific comparison suggests that southern elephant seals grow more than do northern elephant seals, Mirounga angustirostris, and this difference may be related to prey abundance and distribution.

A longitudinal study of senescence in a pinniped

2002 ◽  
Vol 80 (3) ◽  
pp. 395-401 ◽  
Author(s):  
Pierre A Pistorius ◽  
Marthán N Bester
Keyword(s):  
Longitudinal Study ◽  
Adult Female ◽  
No Reduction ◽  
Marion Island ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Reproductive Senescence ◽  
Southern Elephant Seals ◽  
Female Survival ◽  
Breeding Seasons

To measure the prevalence of senescence in southern elephant seals (Mirounga leonina Linn.) at Marion Island, changes in adult-female survival and breeding probabilities with age were quantified. Mark–recapture data that had been collected over a 17-year period were analysed using recently developed software to obtain likelihood estimates of survival and capture probabilities. With recapture effort constant over the study period, capture probabilities during the breeding seasons were used as indices of breeding probabilities. Longevity in the population was assessed from the resighting of tagged and hence known-age individuals. Less than a 1% difference between prime-age survival and post prime age survival was found over 8 cohorts of marked females. In addition, no reduction in survival of very old individuals was detected, suggesting the absence of senescence in terms of reduced survival in southern elephant seals. No evidence of reproductive senescence in terms of reduced breeding probability with age was detected. Mortality throughout the population therefore resulted in no individuals surviving to the age where physiological decline would become a mortality agent or result in failure to breed. Five percent of female southern elephant seals survived to age 10 and 0.5% to age 17.

The diet of southern elephant seals (Mirounga leonina) from Heard Island

1995 ◽  
Vol 73 (8) ◽  
pp. 1519-1528 ◽  
Author(s):  
David J. Slip
Keyword(s):  
Stomach Contents ◽  
First Year ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Important Prey ◽  
Heard Island ◽  
Southern Elephant Seals ◽  
Beaked Whales ◽  
Fish Remains ◽  
Dissostichus Eleginoides

Stomach contents were lavaged from 76 southern elephant seals (Mirounga leonina) at Heard Island between July 1992 and March 1993. Eighty-six percent of stomachs contained cephalopods of 17 species. Numerically the most important was Psychroteuthis glacialis (21.1%), and from estimated biomass the most important was Kondakovia longimana (40.4%). Three other species were also common prey: Moroteuthis knipovitchi (19.4% by estimated biomass), Moroteuthis ingens (13.0%), and Alluroteuthis antarcticus (10.2%). Sixty-six percent of stomachs contained fish remains, and four species, Dissostichus eleginoides, Electrona carlsbergi, E. antarctica, and Gymnoscopelus nicholsi, were identified from otoliths. The diet of adults differed from that of juveniles, particularly pups in their first year. Martialia hyadesi was the most important prey of juveniles and represented 57.1% of estimated biomass consumed. Furthermore, smaller seals ate smaller squid. The species and size of cephalopods eaten by southern elephant seals are similar to those of other Southern Ocean predators, particularly some beaked whales.

First-year survival of southern elephant seals, Mirounga leonina , at sub-Antarctic Macquarie Island

Polar Biology ◽  
1999 ◽  
Vol 21 (5) ◽  
pp. 279-284 ◽  
Author(s):  
Clive R. McMahon ◽  
Harry R. Burton ◽  
Marthan N. Bester
Keyword(s):  
First Year ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Macquarie Island ◽  
Southern Elephant Seals

Deep divers in even deeper seas: habitat use of male southern elephant seals from Marion Island

2012 ◽  
Vol 24 (6) ◽  
pp. 561-570 ◽  
Author(s):  
Trevor Mcintyre ◽  
Horst Bornemann ◽  
Joachim Plötz ◽  
Cheryl A. Tosh ◽  
Marthán N. Bester
Keyword(s):  
Habitat Use ◽  
Mixed Model ◽  
Marion Island ◽  
Mirounga Leonina ◽  
Fracture Zones ◽  
Elephant Seals ◽  
Sea Floor ◽  
Close Proximity ◽  
Southern Elephant Seals ◽  
Migration Strategies

AbstractWe describe the habitat use of 22 male southern elephant seals (Mirounga leonina) satellite tagged at Marion Island between 2004 and 2008. While a few areas of increased utilization appeared to be associated with areas of shallower bathymetry (such as sea-floor ridges and fracture zones), seals in our study did not target other areas of shallow bathymetry within close proximity to Marion Island. Rather, most elephant seals foraged pelagically over very deep water where much variation was evident in diel vertical migration strategies. These strategies resulted in generally deeper and longer dives than what has been reported for male elephant seals from other colonies. No significant differences were recorded for dive durations or dive depths between adults and sub-adults. However, younger animals displayed a positive relationship between dive durations and age, as well as between dive depths and age, while these relationships became negative for older animals. Mixed model outputs suggested that seals increased their aerobic fitness as migrations progressed, enabling them to undertake longer dives. We conclude that Marion Island male elephant seals exhibit much variability in dive strategy and are seemingly capable of exploiting a range of different prey types occurring in various depth layers.

Sign in / Sign up

Export Citation Format

Share Document