Studies on the southern elephant seal, Mirounga leonina (L.). III. The annual cycle in relation to age and sex

Carrick, Robert; Csordas, S. E.; Ingham, S. E.; Keith, K

doi:10.1071/cwr9620119

Cited by 101 publications

(76 citation statements)

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“…Shortly after weaning (approximately 3 wk), these seals (n = 5000) were permanently marked by hot-iron branding as described in McMahon et al (1997McMahon et al ( , 1999McMahon et al ( , 2000, conducted under the Australian Antarctic Animal Ethics Committee (AAS 2265) and the Tasmanian Parks and Wildlife Service ethics approval. Daily searches of all the isthmus beaches (3.6 km), fortnightly searches of the northern third of the island (36 km), where most of the marked seals return to (Carrick et al 1962, McMahon et al 1999, and monthly searches of all the island's beaches (96 km) were made to re-sight branded seals. Capturehistory matrices were constructed from these resight histories of the individual seals.…”

Section: Methodsmentioning

confidence: 99%

Comparison of southern elephant seal populations, and observations of a population on a demographic knife-edge

McMahon¹,

Hindell²,

Burton³

et al. 2005

Mar. Ecol. Prog. Ser.

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The dynamics of animal populations are determined by several key demographic parameters, which vary over time with resultant changes in the status of the population. When managing declining populations, the identification of the parameters that drive such change are a high priority, but are rarely achieved for large and long-lived species. Southern elephant seal populations in the South Indian and South Pacific oceans have decreased by as much as 50% during the past 50 yr. The reasons for these decreases remained unknown. This study used a projected stochastic Leslie-matrix model based on long-term demographic data to examine the potential role of several life-history parameters in contributing to the declines. The models simulated the observed population trends that were independently derived from annual abundance surveys. Small changes in survival and fecundity had dramatic effects on population growth rates. At Macquarie Island for example, a small change (ca. 5%) in survival and fecundity rates resulted in the population reverting from a decreasing one to a population that increased. The vital rates that had the greatest impact on fitness were, in order of importance: (1) juvenile survival, (2) adult survival, (3) adult fecundity and (4) juvenile fecundity. Population viability analysis (PVA) for each of the 2 decreasing populations revealed that there was a high probability of the Marion Island population becoming extinct within the next 150 yr, while the probability of extinction at Macquarie Island was low. The estimated mean times to extinction for each population was 134 yr (95% confidence intervals: 105 to 332 yr) at Marion Island and 564 yr at Macquarie Island (the earliest time to extinction was 307 yr).

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Section: Methodsmentioning

confidence: 99%

Comparison of southern elephant seal populations, and observations of a population on a demographic knife-edge

McMahon¹,

Hindell²,

Burton³

et al. 2005

Mar. Ecol. Prog. Ser.

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“…in the summer of 1802 as being "covered with a prodigious number of amphibians" (seals), but he did not attempt to estimate actual numbers of elephant seals that were there at the time of his visit. As some of the seals were "not less than eight to ten metres long", Peron must have seen a few large adult male stragglers and sub-adult males that would have been ashore, as well as numerous smaller moulting juveniles of both sexes, according to what we know today of the elephant seal's annual cycle (Carrick et al 1962). While the largest seals would undoubtedly have been the sealers' preferred quarry, it is likely that all available seals would have been killed and rendered into oil.…”

Section: Southern Elephant Sealsmentioning

confidence: 99%

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

Ling¹

2002

Aust. Mammalogy

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Ling JK, 2002. Impact of colonial sealing on seal stocks around Australia, New Zealand and subantarctic islands between 150 and 170 degrees East. Australian Mammalogy 24: 117-126.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 18 th to the mid-19 th 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.

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“…breeding, moulting and autumn-winter (Carrick et al 1962, Condy 1979. During the breeding haul-out at McQuarie Island, the harem bulls haul out in increasing numbers f;om August until the end of September.…”

Section: Haul-outmentioning

confidence: 99%

“…The season of the moulting haul-out differs by age-class and sex. Immature seals of both sexes moult during November and December, breeding cows in December, January and February and adult bulls between January and April (Carrick et al 1962, Condy 1979.…”

Section: Haul-outmentioning

confidence: 99%

New records of southern elephant sealsMirounga leoninaL. on the coast of southern Africa

Oosthuizen¹,

David²,

Ross³

1988

South African Journal of Marine Science

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Studies on the southern elephant seal, Mirounga leonina (L.). III. The annual cycle in relation to age and sex

Cited by 101 publications

References 0 publications

Comparison of southern elephant seal populations, and observations of a population on a demographic knife-edge

Comparison of southern elephant seal populations, and observations of a population on a demographic knife-edge

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

New records of southern elephant sealsMirounga leoninaL. on the coast of southern Africa

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