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.

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.

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.

Review of Data on Diets of Beaked Whales: Evidence of Niche Separation and Geographic Segregation

2003 ◽  
Vol 83 (3) ◽  
pp. 651-665 ◽  
Author(s):  
C.D. MacLeod ◽  
M.B. Santos ◽  
G.J. Pierce
Keyword(s):  
Prey Species ◽  
Stomach Contents ◽  
Published Data ◽  
Niche Separation ◽  
Beaked Whale ◽  
Important Prey ◽  
Wide Range ◽  
Dietary Niche ◽  
Beaked Whales ◽  
Fish Remains

This study reviewed published data on dietary preferences of beaked whales (Ziphiidae) from stomach contents analysis. Detailed data were only available for three of the six beaked whale genera (Hyperoodon, Mesoplodon and Ziphius). Stomach samples of these three beaked whale genera primarily contained cephalopod and fish remains, although some also contained crustaceans. Mesoplodon spp. were found to contain the most fish, with some species containing nothing but fish remains, while the southern bottlenose whale (Hyperoodon planifrons) and Cuvier's beaked whale (Ziphius cavirostris) rarely, if ever, contained fish. Of cephalopods identified, Histioteuthid, Gonatid, Cranchiid and Onychoteuthid species usually contributed most to prey numbers and biomass for all beaked whale genera. There was a wide range of species and families of cephalopods recorded from stomach contents, with no obvious preference for bioluminescent prey species, vertical migrating prey species or prey species with specific body compositions. Whales of the genus Mesoplodon generally contained smaller prey, such as cephalopods under 500 g in weight, compared with other beaked whales. Hyperoodon and Ziphius frequently contained much larger cephalopods with many important prey species having a mean weight of over 1000 g. This suggests that Mesoplodon occupies a separate dietary niche from Hyperoodon and Ziphius, which may be an example of niche segregation. In contrast, Hyperoodon and Ziphius appear to occupy very similar dietary niches but have geographically segregated distributions, with Hyperoodon occupying cold-temperate to polar waters and Ziphius occupying warm-temperate to tropical waters.

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

Origins, age composition and change in numbers of moulting southern elephant seals (Mirounga leonina L.) in the Windmill Islands, Vincennes Bay, east Antarctica, 1988 - 2001

2003 ◽  
Vol 30 (3) ◽  
pp. 275 ◽  
Author(s):  
John van den Hoff ◽  
Rupert Davies ◽  
Harry Burton
Keyword(s):  
Mature Male ◽  
East Antarctica ◽  
Mirounga Leonina ◽  
Age Classes ◽  
Age Composition ◽  
Elephant Seals ◽  
Macquarie Island ◽  
Heard Island ◽  
Southern Elephant Seals ◽  
Windmill Islands

We discovered that the number of male southern elephant seals (Mirounga leonina) moulting at wallow sites in the Windmill Islands, Vincennes Bay, Antarctica has decreased by 88% since the last data were presented in 1989. This figure equates to an annual decrease of 6.5%, a figure quite different to the known population trends at the islands from where the seals originate. The seals inhabited four fewer wallows in 2001 than in 1990. Brand and tag resights confirm that seals moulting at Browning Peninsula and Peterson Island originate from Macquarie Island and Heard Island. Male seals aged 1–7+ years of age were present but most (68%) were aged over 7. Males aged 4 years old began to haul out in mid-February while prior to that time only male seals older than 5 years were seen. Timing of moult for particular age classes was similar to that observed at other breeding islands. Trends in the numbers of adolescent and mature male seals hauled out at the sub-antarctic breeding locations require investigation.

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.

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.

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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