Opinion: Projecting the effects of environmental change on Antarctic seals

2008 ◽  
Vol 20 (5) ◽  
pp. 425-435 ◽  
Author(s):  
Donald B. Siniff ◽  
Robert A. Garrott ◽  
Jay J. Rotella ◽  
William R. Fraser ◽  
David G. Ainley
Keyword(s):  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Weddell Seals ◽  
Fur Seals ◽  
Pack Ice ◽  
Fur Seal ◽  
Antarctic Seals

AbstractWe consider how Antarctic seals may respond to changes in climate, realizing that anthropogenic alteration of food webs will influence these responses. The species considered include the ice-obligate - crabeater (Lobodon carcinophaga), Weddell (Leptonychotes weddellii), Ross (Ommataphoca rossii) and leopard (Hydrurga leptonyx) seal - and the ice-tolerant Antarctic fur seal (Arctocephalus gazella) and southern elephant seal (Mirounga leonina). The data analysed are from long-term censuses of Weddell seals in McMurdo Sound (1997–2006), and of Weddell, fur and elephant seals at Arthur Harbour, Antarctic Peninsula (1974–2005). After considering their responses to recent changes in environmental features, as well as projected and current changes to their habitat our conclusions are that the distribution and abundance of 1) crabeater and Weddell seals will be negatively affected by changes in the extent, persistence and type of annual sea ice, 2) Ross and leopard seal will be the least negatively influenced by changes in pack ice characteristics, although, as may be the case for crabeater and Weddell, population size and distribution may be altered through changes in food web dynamics, and 3) southern elephant and fur seals will respond in ways opposite to the pack ice species, but could also be influenced most immediately by changes in their food resources due to factors other than climate.

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.

Impact Of Colonial Sealing On Seal Stocks Around Australia, New Zealand And Subantarctic Islands Between 150 And 170 Degrees East

2002 ◽  
Vol 24 (1) ◽  
pp. 117 ◽  
Author(s):  
JK Ling
Keyword(s):  
New Zealand ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Sources Of Information ◽  
Sea Lions ◽  
Fur Seals ◽  
Fur Seal ◽  
Seal Oil ◽  
The Impact

Details of southern elephant seal oil and fur seal and sea lion skin cargoes have been extracted from a large number of secondary sources dealing with Australian and New Zealand maritime history, which in turn referred to numerous primary sources of information. The data were collated and analysed for ten areas in the south-west Pacific region and published recently in two separate larger works. This review is a synthesis and analysis of the impact of the colonial sealing industry on seal stocks in the region, based on those papers, with some minor revisions and reference to works by other authors. Colonial sealing lasted from the late 18th to the mid- 19th century and was followed by sporadic hunting until the late 1940s. Southern elephant seals (Mirounga leonina) were hunted for their oil; and Australian fur seals (Arctocephalus pusillus doriferus), New Zealand fur seals (Arctocephalus forsteri), Australian sea lions (Neophoca cinerea) and New Zealand sea lions (Phocarctos hookeri) were targeted for their skins and some oil. At least 1,081 tons of elephant seal oil were shipped from King Is. between 1802 and 1819, while 8,380 tons were shipped from Macquarie Is. between 1810 and 1919. More than 1.4 million skins of both species of fur seals were harvested between 1792 and 1949, but only 4,000 Neophoca and 5,700 Phocarctos pelts are recorded as having been shipped by 1840. The Antipodes Islands yielded more than a quarter of the total fur seal skin harvest, and New Zealand and southern Australia each delivered a quarter of the total. Current numbers of the two species of fur seals combined are about a tenth of the crudely estimated size (1.5 million) of the original population. The exploited fur seals and sea lions were probably the same species as occur today at the original sealing localities, apart from Macquarie Is. where the identity of the exploited fur seals remains in doubt. There is some evidence that Maoris and Australian Aborigines hunted seals in pre-European times, resulting in reduced ranges and depleted stocks that were exploited later by colonial sealers.

The skin and hair of the southern elephant seal, Mirounga leonina (Linn.) I. The facial vibrissae

1966 ◽  
Vol 14 (5) ◽  
pp. 855 ◽  
Author(s):  
JK Ling
Keyword(s):  
Elephant Seal ◽  
Sensory Function ◽  
Southern Elephant Seal ◽  
Sweat Glands ◽  
Mirounga Leonina ◽  
Sebaceous Glands ◽  
Elephant Seals

The arrangement, number, and anatomy of the facial vibrissa follicles of the southern elephant seal, Mirounga leonina (Linn.), are described. There are three groups of vibrissae: mystacial, supraorbital, and rhinal, containing approximately 38, 7, and 1 follicles, respectively. These specialized hairs appear to be retained for at least 2 yr and are not shed with the pelage hairs at each annual moult. The histology of the vibrissa follicles and associated organs is described and discussed in relation to their sensory function. Vibrissa follicles of elephant seals are different in anatomy from those described in the mouse and rat: the ringwulst is relatively smaller and, in addition to the sebaceous glands, there are tubular glands of unidentified function but resembling apocrine sweat glands.

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.

Population status and seasonal haulout patterns of the southern elephant seal (Mirounga leonina) at Heard Island

1999 ◽  
Vol 11 (1) ◽  
pp. 38-47 ◽  
Author(s):  
David J. Slip ◽  
Harry R. Burton
Keyword(s):  
Total Population ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Population Status ◽  
Elephant Seals ◽  
Adult Females ◽  
Seal Population ◽  
Heard Island ◽  
One Year

We surveyed the southern elephant seal population at Heard Island regularly from February 1992 to March 1993, and determined the haulout patterns of the major components of the population. While haulout patterns of moulting and immature seals may give broad indices of population trends, the breeding haulout of adult females was the only reliable haulout that could be used to determine annual pup production. During the breeding season 14 277 adult females were counted. Raw counts were corrected using two models, one purely mathematical and the other based on the haulout behaviour of adult female seals. The two models have slightly different assumptions, but both provided good fits to the observed haulout patterns and estimated total population with a coefficient of variation of less than 5%. Total pup production was estimated at between 17 000 and 18 000 for 1992. Previous counts of elephant seals from 1949–51, 1985 and 1987 were corrected using the same models. The two models gave estimates of the population that were within ± 2.5% for all but one year. The population declined by about 50% between 1949 and 1985 but there appears to have been little change from 1985–92. The previous decline may be related to changes in sea-ice.

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.

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.

Lactation and suckling in relation to early growth of the southern elephant seal, Mirounga leonina (L.)

1968 ◽  
Vol 16 (5) ◽  
pp. 739 ◽  
Author(s):  
MM Bryden
Keyword(s):  
Growth Rate ◽  
Elephant Seal ◽  
Milk Composition ◽  
Southern Elephant Seal ◽  
Striking Difference ◽  
Mirounga Leonina ◽  
Milk Samples ◽  
High Incidence ◽  
Delayed Initiation

The growth rate of elephant seal pups during the suckling period is shown to be lower at Macquarie I. than at the Falkland Is. Dependencies. Earlier initiation of suckling and lower suckling frequency occurs in the more rapidly growing Falkland Is. seal pups. The analyses of the milk samples collected from Macquarie I. elephant seal cows at different stages of lactation are reported, and a striking difference in milk composition at the different stages is noted. An attempt to determine quantitatively the milk production of the elephant seal is described, and the inaccuracies of the methods used are discussed, with comments on how a better estimate could be obtained. It is concluded that the principal cause of depressed growth rate of elephant seal pups at Macquarie I. is disturbance within the harems. This disturbance has been alleviated to some extent at the Falkland Is. due to alteration in the structure of the population by long-term sealing operations. Indicative of disturbance within the harems at Macquarie I. were the high incidence of injury noted during dissection of 54 seal pups, the delayed initiation of sucking in new-born pups, and the higher frequency of sucking by pups.

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