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.

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.

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

The influence of body size on dive duration of underyearling southern elephant seals (Mirounga leonina)

2000 ◽  
Vol 251 (4) ◽  
pp. 463-471 ◽  
Author(s):  
Lyn G. Irvine ◽  
Mark A. Hindell ◽  
John van den Hoff ◽  
Harry R. Burton
Keyword(s):  
Body Size ◽  
Dive Duration ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Southern Elephant Seals

Weaning mass and the future survival of juvenile southern elephant seals, Mirounga leonina, at Macquarie Island

2000 ◽  
Vol 12 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Clive R. McMahon ◽  
Harry R. Burton ◽  
Marthán N. Bester
Keyword(s):  
Survival Rates ◽  
First Year ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Macquarie Island ◽  
Fat Reserves ◽  
The Future ◽  
Southern Elephant Seals

Seals that survived their first year were on average 2% and 4% heavier at birth and at weaning than the “non-survivors”. First year survival rates calculated for weaners over 135 kg weaning masses showed these weaners had higher survival rates than those less than 95 kg at weaning (71.55% and 54.15% respectively). Heavy weaners had greater fat reserves than light weaners and gained relatively more mass during lactation. Size, and therefore condition at weaning, influences first year survival.

Having a big nose: structure, ontogeny, and function of the elephant seal proboscis

2007 ◽  
Vol 85 (2) ◽  
pp. 207-220 ◽  
Author(s):  
Simona Sanvito ◽  
Filippo Galimberti ◽  
Edward H. Miller
Keyword(s):  
Body Size ◽  
Phenotypic Selection ◽  
Elephant Seal ◽  
Optical Signal ◽  
Facial Morphology ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
And Function

The proboscis of male elephant seals ( Mirounga Gray, 1827) has been suggested as an example of a secondary sexual trait since Darwin. There has been much speculation about its social function (e.g., optical signal of breeding status, amplification of vocalizations, cue for female choice). However, it has never been studied in detail, probably because its fleshy nature makes measurement difficult. In this paper, we employ photogrammetry to measure the proboscis and facial morphology of a large sample of wild, unrestrained, displaying male southern elephant seals ( Mirounga leonina (L., 1758)). We describe ontogeny and allometry of the proboscis and analyze current phenotypic selection pressures on proboscis traits. We discuss the potential role of the proboscis in optical and acoustic signaling of male resource-holding potential and status. We demonstrate that proboscis size is positively correlated with age and body size independently, and that it is currently under a positive sexual selection pressure when the effect of selection on body size is removed. We suggest that selection on proboscis size is functionally related to the emission of agonistic vocalizations.

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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