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Day 2 - Wildlife

Title: Ecological responses of top predators to climate variability in Eastern Antarctica

Presenter: Mark Hindell

Institute for Marine and Antarctic Studies, University of Tasmania

Authors: MS Hindell1, SD Goldsworthy2, R Harcourt3, M Lea1, CR McMahon4

1 - Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia,,

2 - Marine Environment and Ecology, SAARDI Aquatic Sciences,

3 - Graduate School of Environment, Macquarie University,

4 - Research Institute for the Environment and Livelihoods, Charles Darwin University,


The last two decades have seen considerable climate variability in East Antarctica, dominated by an increasingly positive Southern Annular Mode (SAM), and expressed as increasing extent and duration of sea-ice, changing sea temperatures and wind regimes. Quantifying how top predators in the region have responded to this change is a fundamental first step to understanding how the ecosystem will change under predicted scenarios of on-going change in the region and elsewhere in the Southern Ocean. We measured the ecological responses of four predators with diverse life histories and foraging strategies for which there were also medium to long-term monitoring data sets: southern elephant seals (a deep diving wide-ranging capital breeder), Royal penguins (a euphausiid eating income breeder), Antarctic fur seals (a myctophid eating income breeder) and short-tailed shearwaters (a wide ranging zooplankton feeder) and income breeder). All species demonstrated ecological responses that could be related to SAM, although the nature of the responses and the underlying mechanism for the responses varied among the species. Gestating female elephant seals gained more mass, bred more frequently and weaned larger pups when SAM was positive and when ice extent was greater. Royal penguins exhibited a significant change in their breeding phenology, breeding later in years of positive SAM. The growth rates of fur seal pups at Macquarie Island were negatively correlated to SAM, and fecundity rates decreased as SSTs increased. The numbers of shearwaters breeding in southern Tasmania showed a consistent decline of approximately 15% per annum over a decade which correlated with increasing SAM in the main foraging grounds south of Australia. It appears that Southern Ocean predators are influenced by climate in ways that affect demographic performance and ultimately population size.

Title: Trophic Ecology of Antarctic Megafauna: Insights from Nutritional Physiology

Presenter: Regina Eisert

Gateway Antarctica, University of Canterbury

Authors: Eisert, R.1, Pinkerton, M.2, Oftedal, O.T.3

1 - Gateway Antarctica, University of Canterbury, Christchurch, New Zealand

2 - National Institute for Water and Atmospheric Research, Wellington, New Zealand

3 - Smithsonian Environmental Research Center, Edgewater, MD, USA


Environmental management of Antarctic marine ecosystems requires a robust understanding of trophic ecology. Predators are acutely affected by changes in the abundance and quality of prey (defined as prey composition and energy density), and by increases in the costs of acquiring food.

We compared estimated maintenance energy requirements of key Ross Sea predators (Weddell seal Leptonychotes weddellii, type C killer whale Orcinus orca, Adélie penguin Pygoscelis adeliae, emperor penguin Aptenodytes forsteri) with the metabolisable energy (ME) content of common prey items to (a) determine requirements for different prey types and (b) identify potential vulnerabilities of predators to changes in prey availability, with particular emphasis on the importance of Antarctic silverfish (Pleuragramma antarcticum) for penguins and toothfish (Dissostichus mawsoni) for Weddell seals and killer whales.

Gross energy (GE) content of prey by itself – especially when reported on a dry-matter basis – was a poor predictor of nutritional value or prey requirements, with predicted ME as low as 60% of GE in low-fat prey or taxa containing indigestible components. This has immediate consequences for estimating prey requirements, interpreting the ecological sequelae of observed diet changes (e.g., a change in the proportions of krill vs. fish in penguin diets), or predicting the resilience of predators to changes in prey availability resulting from climate change or fishing.

More data are needed on presence and effect of potentially indigestible prey components (wax esters, chitin) on energy and (macro-)nutrient availability. Future research should address potential limitations due to micro- and trace nutrients (vitamins, minerals) in Antarctic megafauna.

Title: Fur seals in the Frontal Zone: Novel Environmental Performance Indicators from the Southern Ocean

Presenter: Simon Goldsworthy

Marine Environment and Ecology, SAARDI Aquatic Sciences

Authors: S Goldsworthy1, M Hindell2, C McMahon3, R Harcourt4

1 - Marine Environment and Ecology, SAARDI Aquatic Sciences,

2 - Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia,

3 - Research Institute for the Environment and Livelihoods, Charles Darwin University,

4 - Graduate School of Environment, Macquarie University,


The capacity of marine predators to respond to changes in marine resources underpins their ability to persist in times of rapid environmental change. However being able to quantify this is often difficult as it requires ecological datasets that span enough years and enough climate variability to detect an ecological response. Since re-colonisation the fur seal population at Macquarie Island population has been recovering slowly due to its isolation from other major population centres, extensive hybridisation and variation in annual resource abundance and/or quality. Variations in food quantity and quality can have profound effects on animal vital rates. At Macquarie Island, annual fecundity rates in the population are negatively correlated with sea surface temperatures (SSTs) in the foraging grounds during in the preceding autumn months, such that high fecundity follows cooler autumn SSTs. In addition, pup growth rates are negatively correlated with wind run and positive Southern Annular Mode (SAM), suggesting that both local and regional climate have strong effects of pup growth. The variance in both the number and quality of offspring produced in each breeding season is therefore highly sensitive to changes in local environmental conditions, especially warming SSTs. These results are especially significant because they illustrate how easily measured life-history traits for instance reproductive performance of apex predator populations such as fur seals, are affected by oceanographic state at annual and lifetime scales. Maintenance of this program into the future can provide a critical environmental performance indicator for the region, especially if oceanic warming continues.

Title: Macquarie Islands Giant Petrels and the impacts of the Pest Eradication Program

Presenter and Author: Rachael Alderman

Department of Primary Industries, Parks, Water and Environment
Threatened Species and Marine Section
PO Box 44 Hobart, Tasmania, Australia 7001


Macquarie Island hosts globally significant populations of both giant petrel species and their population and demographic trends have been monitored annually since 1995. The Macquarie Island Pest Eradication Program (MIPEP) is a large scale attempt to eradicate rabbits and rodents from the island. The initial aerial baiting phase was initiated in 2010 and successfully completed in July 2011. A multi-year ground hunting phase with shooters and detection dogs is currently underway. Early signs are encouraging, although it is too soon to be confident of the success of the program. There has been a cost to the bird populations. Over 1400 birds are known to have died through primary, secondary and even tertiary brodifacoum poisoning. A substantial number (~30%) of these were giant petrels, predominantly Northern Giant Petrels. We present the chronology and scope of the non-target mortality since the commencement of the program. We discuss the mitigation actions implemented to minimise non-target deaths and the associated monitoring to quantify and characterise the nature of the seabird mortality. Finally, we present the population impacts of this sudden mortality event on Macquarie Islands giant petrels in the context of their long term population trends and consider the longer term demographic consequences.

Keywords: giant petrels, population trends, feral pest eradication, secondary poisoning, Macquarie Island.

Title: Prey field use by top predators in the Southern Ocean: understanding foraging dynamics of macaroni penguins near Heard Island

Presenter: Merel Bedford

Institute of Marine and Antarctic Studies

Authors: Merel Bedford1, Jessica Melbourne-Thomas2, Stuart Corney3

1 - Institute of Marine and Antarctic Studies, Hobart, IMAS – Sandy Bay, Cnr Alexander Street & Grosvenor Street, Sandy Bay Tasmania Australia,

2 - Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania 7050 Australia,

3 - Antarctic Climate and Ecosystems CRC, Hobart, ACE CRC Private Bag 80, Hobart Tasmania 7001,


Diet and foraging dynamics were evaluated for the guard and crèche stages of female macaroni penguins (Eudyptes chrysolophus) from Heard Island. Diet changed significantly between the two stages (p<0.005), from a diet dominated by krill (83%) in the guard stage, to a more variable diet in the crèche stage (43% krill, 33% fish, 23% amphipods). This change in diet corresponded with a change in foraging behaviour between stages. During the guard stage foraging trips were short (17.16±7.2 km), and changed to significantly (p<0.005) longer trips (660±140 km) in the crèche stage. These changes in diet and behaviour lead to interesting questions in comparing habitat use and energy requirements. The prey-field of macaroni penguins was sampled with net and acoustic techniques, and showed that krill is available both close to the island and offshore. Fish, however, are more abundant over deeper waters. Energetically, fish have a higher value than krill (8.4 kJ/g and 5.075 kJ/g respectively). This suggests that macaroni penguins at Heard Island are limited by the distances they can forage in the guard stage, and thus settle for krill as their main food source. However, in the crèche stage, they will feed on a food source higher in energy. This study uses data collected during the 2003/04 Heard Island Predator Prey Ecosystem Study project, and is the first to compare foraging and prey field dynamics with diet and energetics around Heard Island. Results from this project can be used to inform management of Southern Ocean fisheries and Antarctic ecosystems.

Title: A co-ordinated, large-scale study of wintering ecology in a key, Southern Ocean predator

Presenter: Mary-Anne Lea

Institute for Marine and Antarctic Studies, University of Tasmania

Authors: M-A Lea1, BT Arthur1, MN Bester2, ME Goebel3, ID Jonsen4, WC Oosthuizen2, MD Sumner5,
PN Trathan6, A Walters1, MA Hindell1

1 - Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia,,,,

2 - Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa,

3 - NOAA South West Fisheries Science Centre, La Jolla, USA,

4 - Ocean Tracking Network, Department of Biology, Dalhousie University, Halifax, Canada,

5 - Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania 7050 Australia,

6 - British Antarctic Survey, Cambridge, United Kingdom,


Antarctic fur seals (Arctocephalus gazella), numerous sub-Antarctic marine predators, exhibit highly plastic foraging strategies throughout their circumpolar range. In summer months in the southern Atlantic Ocean, which supports the greatest numbers of fur seals, Antarctic krill and mesopelagic fish and squid comprise the diet, while other, smaller populations are more reliant on higher trophic level mesopelagic species. Until recently, the behaviour and trophic context of reproductive females during the 8-month, winter period was unknown. Since 2008, miniature geolocation loggers have been carried by adult females from South Georgia, Cape Shirreff (Antarctic Peninsula), Marion Island and more recently Iles Kerguelen, throughout the winter period to elucidate their migratory movements (n=133 to 2011). By coupling winter tracks with stable isotope analyses of blood and whisker samples, winter consumption of krill, and higher trophic level fish and squid has been identified across virtually all Southern Ocean inter-frontal regions from the continent to the north of the sub-Antarctic Zone. We can now confirm that female Antarctic fur seals adopt markedly different approaches to winter foraging both within and between populations. Antarctic Peninsula animals conduct a single migratory journey, largely to waters north of the sub-Antarctic Zone. In contrast, Marion and Bird Island females performed mixture of migratory and large scale central place foraging behaviour. Of the three populations studied in 2008 and 2009, Bird Island females showed greatest propensity for sea ice associations in waters south of the Polar Front, although certain individuals from Marion Is. and Cape Shirreff displayed punctuated periods of ice-association. Such a co-ordinated, simultaneous, multi-site, long-term deployment permits a comprehensive assessment of the wide diversity of winter habitat needs and preferences of an important Southern Ocean/CEMP consumer.

Latest news

  • Conference prize winners
    27 Jun 2013

    The Strategic Science in Antarctica conference concluded yesterday and two days of workshops have commenced. Congratulations to those who were awarded prizes for their contributions to the conference.

  • Watch the welcome message from Australia's Environment Minister
    24 Jun 2013

    In a welcome message via video from Canberra, Australia’s Environment Minister, Tony Burke, reflected on the foresight of earlier decision-makers who agreed to set aside an entire continent for scientific research.

  • Last minute information for attendees
    20 Jun 2013

    There's not too long to wait until the start of the Strategic Science in Antarctica conference, and we hope you’re as excited as we are! Read on for more information about the final program, registration, Twitter, presenters, posters and social functions.

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Key dates

  • 11th June 2013
    Registrations close
  • 21st June 2013
    Registrations at the AAD open for staff
  • 24th June 2013
    Registrations at the venue open
  • 24th June 2013
    Conference commences
  • 26th June 2013
    Conference concludes

More key dates…

This page was last modified on 6 June 2013.