scholarly journals Bottom-up regulation of a pole-ward migratory predator population

2014 ◽  
Vol 281 (1782) ◽  
pp. 20132842 ◽  
Author(s):  
John van den Hoff ◽  
Clive R. McMahon ◽  
Graham R. Simpkins ◽  
Mark A. Hindell ◽  
Rachael Alderman ◽  
...  
Keyword(s):  
Sea Ice ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Island Population ◽  
Predator Population ◽  
Mirounga Leonina ◽  
Atmospheric Variability ◽  
Macquarie Island ◽  
The Past ◽  
Foraging Range

As the effects of regional climate change are most pronounced at polar latitudes, we might expect polar-ward migratory populations to respond as habitat suitability changes. The southern elephant seal ( Mirounga leonina L.) is a pole-ward migratory species whose populations have mostly stabilized or increased in the past decade, the one exception being the Macquarie Island population which has decreased continuously over the past 50 years. To explore probable causes of this anomalous trend, we counted breeding female seals annually between 1988 and 2011 in order to relate annual rates of population change ( r ) to foraging habitat changes that have known connections with atmospheric variability. We found r (i) varied annually from −0.016 to 0.021 over the study period, (ii) was most effected by anomalous atmospheric variability after a 3 year time lag was introduced ( R = 0.51) and (iii) was associated with sea-ice duration (SID) within the seals’ foraging range at the same temporal lag. Negative r years may be extrapolated to explain, at least partially, the overall trend in seal abundance at Macquarie Island; specifically, increasing SID within the seals foraging range has a negative influence on their abundance at the island. Evidence is accruing that suggests southern elephant seal populations may respond positively to a reduced sea-ice field.

Branding Elephant Seals for life-history studies

Polar Record ◽  
1967 ◽  
Vol 13 (85) ◽  
pp. 447-449 ◽  
Author(s):  
Susan E. Ingham
Keyword(s):  
Ecological Study ◽  
Individual Recognition ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Macquarie Island ◽  
Heard Island ◽  
Antarctic Research

In 1949 the Australian National Antarctic Research Expeditions (ANARE) began a long-term ecological study of the Southern Elephant Seal (Mirounga leonina) at HeardIsland. The biologists devised a method of branding seals for individual recognition (Chittleborough and Ealey, 1953) which has been modified only in detail since then (Carrick and Ingham, 1962a). At Heard Island, pups were branded every year until 1953, but the study here came to an end with the closing of the ANARE station in 1955. At Macquarie Island, pups have been branded every year from 1951 to 1965, giving a sample of individuals of known age and known history.

The Southern Elephant Seal, Mirounga leonina (L.), in the Vestfold Hills, Antarctica

1977 ◽  
Vol 4 (1) ◽  
pp. 13 ◽  
Author(s):  
TJ Tierney
Keyword(s):  
Sea Ice ◽  
Satellite Data ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Local Distribution ◽  
Vestfold Hills

The southern elephant seal regularly hauls out to moult at the Vestfold Hills, Antarctica. The population comprises mostly immature males. Local distribution and movement were assessed by a marking program. Marked seals returned the following year, demonstrating an annual constancy to site. The wallow sites of the area are described. No correlation was found between wallow population and macroclimate. Satellite data on sea ice were used in an attempt to determine the influence of the annual sea ice cycle on this population.

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.

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.

Human disturbance, nursing behaviour, and lactational pup growth in a declining southern elephant seal (Mirounga leonina) population

2002 ◽  
Vol 80 (11) ◽  
pp. 1876-1886 ◽  
Author(s):  
Georg H Engelhard ◽  
Antonie N.J Baarspul ◽  
Martijn Broekman ◽  
Jeroen C.S Creuwels ◽  
Peter J.H Reijnders
Keyword(s):  
Human Disturbance ◽  
Population Decline ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Maternal Aggression ◽  
Human Presence ◽  
Macquarie Island ◽  
Southern Elephant Seals ◽  
Pup Growth

We studied lactation behaviour in relation to pup growth in southern elephant seals (Mirounga leonina) at Macquarie Island, and compared harems in areas of high and low human presence to determine if there is an effect attributable to human activities, including scientific research. Pup weaning mass, a known correlate of first–year survival, was positively influenced by suckle bout durations during early and middle lactation and by maternal aggression during late lactation; no other behavioural variables were associated with weaning mass. In the area of high human presence, we observed from a distance the behaviour of mother–pup pairs directly before, during, and after visits to harems by other researchers. Alertness was raised threefold in the presence of people but quickly returned to predisturbance levels after their departure; there were no significant short-term effects on other behavioural variables. In the areas of high and low human presence, we observed the undisturbed behaviour of the seals in the absence of other people. No significant differences in any behavioural variables examined were found, indicating no long-term changes in behaviour resulting from human presence. Human disturbance therefore appears not to have significantly contributed to the population decline observed at Macquarie Island, but the conclusion requires caution given the fairly low power of our analyses.

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