LONGEVITY, FERTILITY AND PHILOPATRY OF TWO FEMALE SOUTHERN ELEPHANT SEALS (<i>MIROUNGA LEONINA</i>) AT MACQUARIE ISLAND

Hindell, Mark A.; Little, G. J.

doi:10.1111/j.1748-7692.1988.tb00197.x

Cited by 44 publications

(29 citation statements)

References 6 publications

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“…This is supported by the observation that males (but not females) tagged in SG have been resighted at the Falkland islands. Markrecapture studies in PV (Lewis et al 1996) and in MQ (Nicholls 1970;Hindell & Little 1988) found resightings of about 80% of females within a few kilometres of their place of birth. Out of those animals resighted on haulouts away from PV (50^1000 km), most were males.…”

Section: Discussion (A) Genetic Di¡erentiationmentioning

confidence: 99%

Genetic and morphometric differentiation between island and mainland southern elephant seal populations

Hoelzel

Campagna

Arnbom

2001

Proc. R. Soc. Lond. B

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We compare genetic (both nuclear and mitochondrial) and morphometric measures between two putative populations of southern elephant seal (Mirounga leonina), and interpret the results in the context of data from mark-recapture and satellite-telemetric studies. One population is on the Argentine mainland, while the other is 2400 km away on South Georgia island. We found pronounced di¡erentiation at the mitochondrial DNA (mtDNA) control region that was distinct from the pattern of variation seen among island rookeries. Some morphometric characters and seven out of ten nuclear-DNA markers also showed di¡erentiation between the island and mainland sites. Diversity at nuclear markers was high in both populations but mtDNA diversity was low in the mainland population, suggesting a founder event and little subsequent immigration of females. Morphological di¡erences may suggest di¡erent selective environments at the two sites.

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Section: Discussion (A) Genetic Di¡erentiationmentioning

confidence: 99%

Genetic and morphometric differentiation between island and mainland southern elephant seal populations

Hoelzel

Campagna

Arnbom

2001

Proc. R. Soc. Lond. B

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“…Although elephant seals travel long distances to forage, the Macquarie Island population is considered an isolated breeding group and is the only major Pacific sector breeding group in the Southern Ocean (McMahon et al 2006). In addition, females exhibit a high degree of philopatry (giving birth 1-4 km from their birth site) (Nicholls 1970, Hindell andLittle 1988), and the island is comparatively small (34 km long by 5 km wide at its widest), making inter-annual resights of individuals possible. From 1993From -1999, approximately 2000 pups per year were tagged with uniquely numbered plastic tags in both hind flippers within 24 hours of birth and subsequently recaught and branded at weaning (Table 1).…”

Section: Data Collectionmentioning

confidence: 99%

The implications of assuming independent tag loss in southern elephant seals

et al. 2012

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Abstract. Survival and reproductive rate estimation requires following uniquely identified individuals through time, and many statistical models assume markings used to identify individuals are permanent. However, survival rates are underestimated when single marks are lost, since the models will effectively score those animals as dead. In order to account for mark loss, some researchers use a double-mark approach, assuming the probability of losing one mark is independent of losing the other one. Therefore, mark loss can be estimated using animals that have lost one mark. Using a 17-year dataset of southern elephant seals (Mirounga leonina) marked with permanent brands and two cattle tags in their hind flippers, we were able to compare tag loss and survival rate estimates with and without the assumption of independent tag loss with respect to age, sex, and wean mass. We demonstrate the assumption of independent tag loss is not valid, showing it is more likely for an animal to lose both tags than just one or the other. The assumption of independent tag loss leads to an underestimate of survival rates which in turn leads to underestimates of population growth rate. In addition, tag loss rates are different by sex and age, with older males more likely to lose tags. Tag loss is also a quadratic function of wean mass through age two, with smaller and larger animals more likely to lose both tags. Such differences are possibly due to differences in behavior, flipper growth, and immune response. Using a Bayesian approach, we will be able to use our tag loss estimates as priors in future analyses for a subset of marked animals that only have flipper tags. With this population, the independent tag loss models are more likely to incorrectly estimate a declining population (growth rate , 1.0), potentially leading to unwarranted management action. To account for non-independent mark loss in survival rate studies, we recommend researchers use at least two forms of marking on at least a subset of animals. However, neither form of marking need be permanent as long as mark loss is independent between the different forms.

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“…At Peninsula Valdes, 96% of females that came ashore gave birth, and in the Falkland Islands, 100% (Campagna et al 1993;Galimberti & Boitani 1999). The successful pupping by the 23 year old females seen by Hindell & Little (1988) suggest that there may be no reproductive senescence.…”

Section: Age and Mortalitymentioning

confidence: 99%

“…At Marion Island males do not generally live beyond 13 years, and 93% of females do not reach 14 years (Hindell 1991;Pistorius et al 1999). However, females branded as pups on Macquarie Island have been seen alive and still successfully breeding at 23 years of age (Hindell & Little 1988). Females first bred at between 4 and 7 years of age (mean at Macquarie Island 5.2 ± 1.8 years) and the estimated annual fecundity rate at South Georgia was 0.391 (Hindell 1991).…”

Section: Age and Mortalitymentioning

confidence: 99%

Advances in New Zealand mammalogy 1990–2000: Pinnipeds

Harcourt

2001

Journal of the Royal Society of New Zealand

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LONGEVITY, FERTILITY AND PHILOPATRY OF TWO FEMALE SOUTHERN ELEPHANT SEALS (MIROUNGA LEONINA) AT MACQUARIE ISLAND

Cited by 44 publications

References 6 publications

Genetic and morphometric differentiation between island and mainland southern elephant seal populations

Genetic and morphometric differentiation between island and mainland southern elephant seal populations

The implications of assuming independent tag loss in southern elephant seals

Advances in New Zealand mammalogy 1990–2000: Pinnipeds

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