The importance of land-based prey for sympatrically breeding giant petrels at sub-Antarctic Marion Island

2007 ◽  
Vol 19 (1) ◽  
pp. 25-30 ◽  
Author(s):  
P.J. Nico de Bruyn ◽  
John Cooper ◽  
Marthán N. Bester ◽  
Cheryl A. Tosh
Keyword(s):  
Breeding Success ◽  
Population Regulation ◽  
Elephant Seal ◽  
Population Trends ◽  
Southern Elephant Seal ◽  
Marion Island ◽  
Giant Petrel ◽  
Mirounga Leonina

Northern (Macronectes halli) and southern (M. giganteus) giant petrels breed at different times at sub-Antarctic Marion Island. Long-term census and breeding success data are used to test for competitive overlap between the two species by correlating population trends with those of land-based prey/carrion species. No parameter was singularly important in population regulation of either giant petrel species and the assumed dependence of breeding northern giant petrels on southern elephant seal Mirounga leonina carrion is not entirely supported.

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.

Marion Island elephant seals: the paucity-of-males hypothesis tested

1999 ◽  
Vol 77 (10) ◽  
pp. 1547-1554 ◽  
Author(s):  
I S Wilkinson ◽  
R J van Aarde
Keyword(s):  
Sexual Activity ◽  
Sex Ratios ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Marion Island ◽  
Mirounga Leonina ◽  
Breeding Sites ◽  
Research Activities ◽  
Mating Opportunities ◽  
The Relationship

The southern elephant seal, Mirounga leonina, population at Marion Island has declined since the start of research activities there in 1973, as have populations at other Indian Ocean breeding sites. One suggested mechanism for the decline at Marion Island is a shortage of males, resulting in low insemination rates. We tested this "paucity-of-males" hypothesis by looking at (i) adult sex ratios, (ii) male sexual activity, and (iii) the relationship between levels of sexual activity and the probability of a cow pupping in the following season. Sex ratios were similar to those at other sites where populations are either stable (South Georgia) or increasing (Peninsula Valdes). Dominant bulls monopolised mating opportunities, achieving 98.1% of 629 observed copulations over three seasons. Of the 138 cows coming ashore, only 4 (2.9%) were not seen mating and 89% copulated with only one bull; dominant bulls copulated with all but 1 of the 134 (99.3%) cows that did mate. Cows were mated more frequently than at sites with stable and increasing populations. There was no difference in the observed level of sexual activity between cows seen pupping in the following season and those who failed to pup. This indicates that bulls monopolising harems are capable of inseminating all the cows. Such findings refute the paucity-of-males hypothesis.

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.

Tag-loss in southern elephant seals, Mirounga leonina, at Marion Island

1997 ◽  
Vol 9 (2) ◽  
pp. 162-167 ◽  
Author(s):  
I.S. Wilkinson ◽  
M.N. Bester
Keyword(s):  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Island Population ◽  
Marion Island ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Tag Loss ◽  
Southern Elephant Seals ◽  
Marking Technique ◽  
Loss Rates

Rates of tag-loss are determined for Dalton Jumbo Rototags applied to the hind flippers of 4343 (2208 males, 2135 females) southern elephant seal (Mirounga leonina) pups at Marion Island over an eight year period from 1983–1990 as part of a demographic study of the species. Loss rates were the lowest recorded to date for this species (range 0.0–9.1%). No significant relationship existed between age and rate of tag-loss, neither was there any sex or year related differences in age-specific tag-loss rates. The low rates of loss highlight the value of tagging as a marking technique, and allow for high levels of confidence in the reliability of the population parameters that are derived from the tagging data collected for the Marion Island population.

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.

Seasonal movements and foraging areas of adult southern female elephant seals, Mirounga leonina, from Marion Island

1998 ◽  
Vol 10 (1) ◽  
pp. 21-30 ◽  
Author(s):  
F. C. Jonker ◽  
M. N. Bester
Keyword(s):  
Elephant Seal ◽  
Outer Edge ◽  
Foraging Strategies ◽  
Southern Elephant Seal ◽  
Antarctic Polar Front ◽  
Marion Island ◽  
Mirounga Leonina ◽  
Seasonal Movements ◽  
Frontal Zones ◽  
The Antarctic

Seasonal movements and foraging areas of postbreeding (n = 9) and postmoulting (n = 3) adult southern elephant seal females from Marion Island were studied using Geolocation Time-depth Recorders. Movements were classified into three phases – an outbound transit phase, distant foraging phase, and an inbound transit phase. The longest residence time of postbreeding females during their foraging migrations was in areas at the outer edge of their feeding range (± 1460 km) both to the north and south of the island, largely within inter-frontal zones south of the Antarctic Polar Front (APF) and between the Sub-Tropical Convergence (STC) and the Sub-Antarctic Front (SAF). Postmoulting females travelled further afield (2122–3133 km distant) to the APF, to inter-frontal zones south of the APF (within the pack ice outer edge), as well as to the Antarctic Continental Shelf. This study provides additional information on the putative function of dive types in relation to the movement phases of elephant seal females from Marion Island. The relative frequency of assumed ‘foraging’, ‘exploratory’ and ‘transit’ dive types, as well as the duration and location of the different phases of movement suggest two seasonal foraging strategies. Sea floor topography could possibly cue the transit phases of both postbreeding and postmoulting females from Marion Island.

scholarly journals The northernmost haulout site of South American sea lions and fur seals in the western South Atlantic

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Natália Procksch ◽  
M. Florencia Grandi ◽  
Paulo Henrique Ott ◽  
Karina Groch ◽  
Paulo A. C. Flores ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
South American ◽  
Mirounga Leonina ◽  
Sea Lions ◽  
Significant Difference ◽  
Northern Portion ◽  
Kernel Density Analysis

AbstractWe present estimates of the seasonal and spatial occupation by pinnipeds of the Wildlife Refuge of Ilha dos Lobos (WRIL), based on aerial photographic censuses. Twenty aerial photographic censuses were analysed between July 2010 and November 2018. To assess monthly differences in the numbers of pinnipeds in the WRIL we used a Generalized Linear Mixed Model. Spatial analysis was carried out using Kernel density analysis of the pinnipeds on a grid plotted along the WRIL. Subadult male South American sea lions (Otaria flavescens) were the most abundant pinniped in the WRIL. Potential females of this species were also recorded during half of the census. The maximum number of pinnipeds observed in the WRIL was 304 in September 2018, including an unexpected individual southern elephant seal (Mirounga leonina), and a high number of South American fur seal yearlings (Arctocephalus australis). However, there was no statistically significant difference in counts between months. In all months analysed, pinnipeds were most often found concentrated in the northern portion of the island, with the highest abundances reported in September. This study confirms the importance of the WRIL as a haulout site for pinnipeds in Brazil, recommends that land research and recreational activities occur in months when no pinnipeds are present, and encourages a regulated marine mammal-based tourism during winter and spring months.

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