PenguinScience | Papers, Books











<< Right click 'save as' to download complete papers in PDF format

Ecological Monographs, 80(1), 2010, pp. 49–66
Antarctic penguin response to habitat change as Earth’s troposphere reaches 28C above pre-industrial levels

1HT Harvey and Associates, 983 University Avenue, Building D, Los Gatos, CA 95032 USA
2Department of Geosciences, University of Arizona, Tucson, AZ 85721 USA
3Department of Biology, Woods Hole Oceanographic Institution, MS 34, Woods Hole, MA 02543 USA
4School of Zoology, University of Tasmania, Sandy Bay, Tasmania 7005 Australia
5Landcare Research, P.O. Box 40, Lincoln 7640 New Zealand
6Polar Oceans Research Group, Sheridan, MT 59749 USA
7Scripps Institution of Oceanography, La Jolla, CA 92093 USA

Abstract. We assess the response of pack ice penguins, Emperor (Aptenodytes forsteri) and Adélie (Pygoscelis adeliae), to habitat variability and, then, by modeling habitat alterations, the qualitative changes to their populations, size and distribution, as Earth’s average tropospheric temperature reaches 28C above pre-industrial levels (ca. 1860), the benchmark set by the European Union in efforts to reduce greenhouse gases. First, we assessed models used in the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) on penguin performance duplicating existing conditions in the Southern Ocean. We chose four models appropriate for gauging changes to penguin habitat: GFDL-CM2.1, GFDL-CM2.0, MIROC3.2(hi-res), and MRI-CGCM2.3.2a. Second, we analyzed the composited model ENSEMBLE to estimate the point of 28C warming (2025–2052) and the projected changes to sea ice coverage (extent, persistence, and concentration), sea ice thickness, wind speeds, precipitation, and air temperatures. Third, we considered studies of ancient colonies and sediment cores and some recent modeling, which indicate the (space/time) large/centennial scale penguin response to habitat limits of all ice or no ice. Then we considered results of statistical modeling at the temporal interannual-decadal scale in regard to penguin response over a continuum of rather complex, meso- to large-scale habitat conditions, some of which have opposing and others interacting effects. The ENSEMBLE meso/decadal-scale output projects a marked narrowing of penguins’ zoogeographic range at the 28C point. Colonies north of 708 S are projected to decrease or disappear: ~50% of Emperor colonies (40% of breeding population) and ~75% of Adélie colonies (70% of breeding population), but limited growth might occur south of 738 S. Net change would result largely from positive responses to increase in polynya persistence at high latitudes, overcome by decreases in pack ice cover at lower latitudes and, particularly for Emperors, ice thickness. Adélie Penguins might colonize new breeding habitat where concentrated pack ice diverges and/or disintegrating ice shelves expose coastline. Limiting increase will be decreased persistence of pack ice north of the Antarctic Circle, as this species requires daylight in its wintering areas. Adélies would be affected negatively by increasing snowfall, predicted to increase in certain areas owing to intrusions of warm, moist marine air due to changes in the Polar Jet Stream.


Aquatic Mammals 2009, 35(3), 335-347
An Apparent Decrease in the Prevalence of “Ross Sea Killer Whales” in the Southern Ross Sea

David G. Ainley,1 Grant Ballard,2 and Silvia Olmastroni3
1H. T. Harvey & Associates, 983 University Avenue, Los Gatos, CA 95032, USA; E-mail: 2PRBO Conservation Science, Petaluma, CA 94954, USA, and Ecology, Evolution, and Behaviour, School of Biological Sciences, University of Auckland, New Zealand3Dipartimento Scienze Ambientali, Universita di Siena, Via Mattioli 4 53100 Siena, Italy

Abstract Killer whales (Orcinus orca), both ecotype-B and -C, are important to the Ross Sea, Antarctic ecosystem. The ecotype-C is referred to as “Ross Sea [RS] killer whale.” Herein, we review data on occurrence patterns and diet of RS killer whales and present new information on numbers observed in the southwestern Ross Sea, 2002-2003 to 2008-2009 austral summers. These “resident” whales appear to feed principally on fish, including the large Antarctic toothfish (Dissostichus mawsoni). On the basis of sea watches from Cape Crozier, Ross Island, sighting frequency and average group size appears to have decreased; prevalence as indicated by casual observations from helicopter pilots flying over the area on a daily basis has also decreased in nearby McMurdo Sound. Consistent with a decrease in the catch-per-unit-effort of sci­entific fishing for toothfish in McMurdo Sound, we suggest and review evidence that the change in RS killer whale numbers in the southern Ross Sea is related to an industrial fishery-driven, density-dependent northward contraction of the toothfish stock and not to changes in the physical (and, in turn, biological) environment. We surmise that in this closely coupled foodweb, composed of very abundant penguin, seal, and whale components, loss of the toothfish option for RS killer whales would force more direct competition with other predators for capture of the smaller-fish prey. Therefore, we propose, the RS killer whales have opted to move elsewhere, in a scenario consistent with that of the Pacific coast of Canada, where numbers of resident killer whales have decreased following the loss of large fish as a prey choice.


MARINE MAMMAL SCIENCE, 26(2): 482–498 (April 2010)
Impacts of cetaceans on the structure of Southern Ocean food webs

H. T. Harvey & Associates, 983 University Avenue, Building D, Los Gatos, California 95032, U.S.A.
PRBO Conservation Science, Petaluma, California 94954, U.S.A.
Centre for Applied Conservation Research, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
Department of Geological Sciences, University of Texas at San Antonio, San Antonio, Texas 78249, U.S.A.
Biology and Marine Biology, University of North Carolina, Wilmington, North Carolina 28403, U.S.A.
H. T. Harvey & Associates, 983 University Avenue, Building D, Los Gatos, California 95032, U.S.A.
Dipartimento Scienze Ambientali, Universit`a di Siena, Via Mattioli 4, 53100 Siena, Italy
Wildlife Ecology & Consulting, 709 56th Street, Oakland, California 94609, U.S.A.
P. O. Box 438, West Falmouth, Massachusetts 02574, U.S.A.
17 Modena Crescent, Auckland, New Zealand
School of Zoology, University of Tasmania, Sandy Bay, Tasmania 7005, Australia

Recently, Ballance et al. (2006) revived the hypothesis that cetaceans were a major
force in the structuring of Southern Ocean food webs, and suggested that they are
still playing a keystone role even as their loss continues (see also review in Mori and
Butterworth 2006), a subject that we herein would like to emphasize. According
to this hypothesis, following 60 yr of directed industrial whaling (Tønnessen and
Johnsen 1982, Baker and Clapham 2002), the demise of the great whales (blue,
Balaenoptera musculus intermedia; fin, B. physalus; and humpback, Megaptera novaeangliae) led to changes in populations and demographic parameters among penguins,
seals, and minke whales (B. bonaerensis; see also Laws 1977, Bengtson and Laws
1985). These changes to populations of the great whales’ competitors came about
upon release from trophic competition as a result of the “krill surplus” that ensued
(i.e., of Antarctic krill, Euphausia superba; Bengtson and Laws 1985).
Despite its popularity among Southern Ocean ecologists 25 yr ago, this top-down
hypothesis (consumer effects on resources) has been largely replaced by an emphasis
on bottom-up explanations (resource effects on consumers), as summarized in Ainley
et al. (2007).


Antarctic Science 21(4), 317–327 (2009)
The importance of Antarctic toothfish as prey of Weddell
seals in the Ross Sea

1HT Harvey & Associates, Los Gatos, CA 95032, USA
2Department of Ecology, Evolution and Behavioral Biology, University of Minnesota, St Paul, MN 55108, USA

Abstract: Uncertainty exists over the importance of Antarctic toothfish (Dissostichus mawsoni) as prey of top predators in the Ross Sea. In this paper we assess relative weight given to direct, observational evidence of prey taken, as opposed to indirect evidence from scat and biochemical analysis, and conclude that toothfish are important to Weddell seals (Leptonychotes weddellii). The seals eat only the flesh of large toothfish and therefore they are not detected in scat or stomach samples; biochemical samples have been taken from seal sub-populations where toothfish seldom occur. Using direct observations of non-breeding seals away from breeding haulouts in McMurdo Sound, 0.8–1.3 toothfish were taken per day. Based on these and other data, the non-breeding portion of the McMurdo Sound seal population, during spring and summer, consume about 52 tonnes of toothfish. Too many unknowns exist to estimate the non-trivial amount consumed by breeders. We discuss why reduced toothfish availability to Weddell seals, for energetic reasons, cannot be compensated by a switch to silverfish (Pleuragramma antarcticum) or squid. The Ross Sea toothfish fishery should be reduced including greater spatial management, with monitoring of Weddell seal populations by CCAMLR. Otherwise, probable cascades will lead to dramatic changes in the populations of charismatic megafauna.


Marine Ecology Progress Series,  405: 287–302, 2010
Foraging strategies of Adélie penguins: adjusting
body condition to cope with environmental

Grant Ballard1, 2,*, Katie M. Dugger3, Nadav Nur1, David G. Ainley4
1PRBO Conservation Science, 3820 Cypress Drive #11, Petaluma, California 94954, USA
2School of Biological Sciences, University of Auckland, Auckland, New Zealand
3Oregon State University, Department of Fisheries and Wildlife, 104 Nash Hall, Corvallis, Oregon 97331-3803, USA
4H. T. Harvey & Associates, 983 University Avenue, Bldg. D, Los Gatos, California 95032, USA

ABSTRACT: Animals modulate breeding effort by balancing investment in self-maintenance against investment in their young, potentially impacting reproductive success when faced with difficult conditions. This life history trade-off model has been evaluated for flying birds, especially those that forage over large pelagic regions of relatively sparse prey availability. We evaluated its applicability to penguins which, lacking flight, depend on reliably available prey relatively close to colonies. We used transponders and an automated weighing system to monitor 40 to 75 breeding Adélie penguins Pygoscelis adeliae per season for 10 seasons, while environmental conditions varied dramatically,
measuring foraging trip duration, parental mass change, and total food load delivered to chicks. Parents that lost the most mass during breeding provided more food to chicks while maintaining their own condition. In contrast, in years when adult mass was lower to begin with, parents recovered their own condition and delivered less food to chicks. Food loads were also related to environmental variables, with parents making longer trips and delivering less food when access to prey was more difficult, but delivering more food to 2-chick broods than to 1-chick broods. Penguins did not alternate between short (chick provisioning) and long (self-maintenance) trips, as has been observed in farranging seabirds. Nevertheless, our results indicate they regulated their condition depending on environmental and physiological factors, with impacts on the amount of food delivered to young and pre-fledging mass. Parental choice of multiple foraging habitats and depletion of prey in the nearest habitat due to intraspecific competition have important implications in explaining contrasting patterns observed among studies investigating the life history trade-off model in birds.


Ecology, 91(7), 2010, pp. 2056–2069
Responding to climate change: Adélie Penguins confront astronomical and ocean boundaries

1PRBO Conservation Science, 3820 Cypress Drive #11, Petaluma, California 94954 USA; 2Ecology, Evolution, and Behaviour, School of Biological Sciences, University of Auckland, Auckland, New Zealand
3Department of Environmental Earth System Science, Ocean Biogeochemistry Lab, Stanford University,
Stanford, California 94305-2215 USA
4HT Harvey & Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118 USA
5Cryospheric Sciences Branch, NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771 USA
6British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road,
Cambridge CB3 0ET United Kingdom

Abstract. Long-distance migration enables many organisms to take advantage of lucrative breeding and feeding opportunities during summer at high latitudes and then to move to lower, more temperate latitudes for the remainder of the year. The latitudinal range of the Adélie Penguin (Pygoscelis adeliae) spans 22 degrees latitude. Penguins from northern colonies may not migrate, but due to the high latitude of Ross Island colonies, these penguins almost certainly undertake the longest migrations for the species. Previous work has suggested that Adélies require both pack ice and some ambient light at all times of year. Over a three-year period, which included winters of both extensive and reduced sea ice, we investigated characteristics of migratory routes and wintering locations of Adélie Penguins from two colonies of very different size on Ross Island, Ross Sea, the southernmost colonies for any penguin. We acquired data from 3–16 geolocation sensor tags (GLS) affixed to penguins each year at both Cape Royds and Cape Crozier in 2003–2005. Migrations averaged 12 760 km, with the longest being 17 600 km, and were in part facilitated by pack ice movement. Trip distances varied annually, but not by colony. Penguins rarely traveled north of the main sea-ice pack, and used areas with high sea-ice concentration, ranging from 75% to 85%, about 500 km inward from the ice edge. They also used locations where there was some twilight (2–7 h with sun <6 degrees below the horizon). We report the present Adélie Penguin migration pattern and conjecture on how it probably has changed over the past 12 000 years, as the West Antarctic Ice Sheet withdrew southward across the Ross Sea, a situation that no other Adélie Penguin population has had to confront. As sea ice extent in the Ross Sea sector decreases in the near future, as predicted by climate models, we can expect further changes in the migration patterns of the Ross Sea penguins.


Proc Natl Acad Sci, doi 10.1073/pnas 1000623107
Survival differences and the effect of environmental instability on breeding dispersal in an Adélie penguin meta-population

Katie M. Dugger,1, David G. Ainley.2, Phil O’B. Lyver,3, Kerry Barton,4, and Grant Ballard, 5
1Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331-3803; 2H. T. Harvey and Associates, Wildlife Ecology, Los Gatos, CA 95032; 3Landcare Research, Lincoln 7640, New Zealand; 4Landcare Research, Private Bag 6, Nelson Mail Centre, Nelson 7042, New Zealand; 5PRBO Conservation Science, Petaluma, CA 94954; and Ecology, Evolution, and Behaviour, School of Biological Sciences, University of Auckland, Auckland, New Zealand

High survival and breeding philopatry was previously confirmed for the Adélie penguin (Pygoscelis adeliae) during a period of stable environmental conditions. However, movements of breeding adults as a result of an unplanned natural experiment within a four colony meta-population provided interesting insights into this species’ population dynamics. We used multistate mark-recapture models to investigate apparent survival and dispersal of breeding birds in the southwestern Ross Sea during 12 breeding seasons (1996–2007). The natural experiment was facilitated by the temporary grounding of two immense icebergs that (i) erected a veritable fence separating colonies and altering migration routes and (ii) added additional stress by trapping extensive sea ice in the region during 5 of 12y. Colony size varied by orders of magnitude, allowing investigation of apparent survival and dispersal rates in relation to both environmental conditions and colony size within this meta-population. Apparent survival was lowest for the smallest colony (4,000 pairs) and similar for the medium (45,000 pairs) and large colonies (155,000 pairs), despite increased foraging effort expended by breeders at the largest colony. Dispersal of breeding birds was low (<1%), except during years of difficult environmental conditions when movements increased, especially away from the smallest colony (3.5%). Decreased apparent survival at the smallest colony could reflect differences in migration chronology and winter habitat use compared with the other colonies, or it may reflect increased permanent emigration to colonies outside this meta-population. Contrary to current thought, breeding penguins are not always philopatric. Rather, stressful conditions can significantly increase dispersal rates.


Ecology, 91(7), 2010, pp. 2044–2055
Working less to gain more: when breeding quality relates to foraging efficiency

1CEBC-CNRS, UPR 1934, 79360 Villiers en Bois, France
2H. T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118 USA
3PRBO (Point Reyes Bird Observatory) Conservation Science, 3820 Cypress Drive #11, Petaluma, California 94954 USA; 4Ecology, Evolution, and Behaviour, School of Biological Sciences, University of Auckland, Auckland, New Zealand
5Department of Environmental Earth System Science, Ocean Biogeochemistry Lab, Stanford University,
Stanford, California 94305-2215 USA
6Landcare Research, Private Bag 6, Nelson, New Zealand
7Landcare Research, P.O. Box 40, Lincoln, New Zealand

Abstract. In animal populations, a minority of individuals consistently achieves the highest breeding success and therefore contributes the most recruits to future generations. On average, foraging performance is important in determining breeding success at the population level, but evidence is scarce to show that more successful breeders (better breeders) forage differently than less successful ones (poorer breeders). To test this hypothesis, we used a 10-year, three-colony, individual-based longitudinal data set on breeding success and foraging parameters of a long-lived bird, the Adélie Penguin, Pygoscelis adeliae. Better breeders foraged more efficiently than poorer breeders under harsh environmental conditions and when
offspring needs were higher, therefore gaining higher net energy profit to be allocated to reproduction and survival. These results imply that adverse ‘‘extrinsic’’ conditions might select breeding individuals on the basis of their foraging ability. Adélie Penguins show sufficient phenotypic plasticity that at least a portion of the population is capable of surviving and successfully reproducing despite extreme variability in their physical and biological environment, variability that is likely to be associated with climate change and, ultimately, with the species’ evolution. This study is the first to demonstrate the importance of ‘‘extrinsic’’
conditions (in terms of environmental conditions and offspring needs) on the relationship between foraging behavior and individual quality.


Antarctic Science 20: 425-435
Projecting the effects of environmental change on Antarctic seals

1Department of Ecology, Evolution and Behavioral Biology, University of Minnesota, 100 Ecology Building, St Paul, MN 55108, USA
2Ecology Department, Montana State University, 310 Lewis Hall, Bozeman, MT 59717, USA
3Polar Oceans Research Group, PO Box 368, Sheridan, MT 59749, USA
4H.T. Harvey & Associates, 983 University Avenue, Los Gatos, CA 95032, USA

Abstract: We 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.


Impacts of local human activities on the Antarctic environment

1Antarctic Southern Ocean Coalition (ASOC), BP 80358, 45163 Olivet, CEDEX 3, France
2Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, UK
3British Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge CB3 0ET, UK
4H.T. Harvey and Associates, 983 University Avenue, Bldg D, Los Gatos, CA 95032, USA
5Instituto de Ecologı´a y Evolucio´n, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
6University of Jena, Dornburger Str. 159, D-07743 Jena, Germany
7School of Geography and Environmental Studies, University of Tasmania, Private Bag 78, Hobart, TAS 7001, Australia
8Australian Antarctic Division, Channel Highway, Kingston, TAS 7050, Australia
9current address: University of Potsdam, Maulbeerallee 1, D-14469 Potsdam, Germany

Abstract: We review the scientific literature, especially from the past decade, on the impacts of human
activities on the Antarctic environment. A range of impacts has been identified at a variety of spatial and
temporal scales. Chemical contamination and sewage disposal on the continent have been found to be
long-lived. Contemporary sewage management practices at many coastal stations are insufficient to prevent local contamination but no introduction of non-indigenous organisms through this route has yet been demonstrated. Human activities, particularly construction and transport, have led to disturbances of flora and fauna. A small number of non-indigenous plant and animal species has become established, mostly on the northern Antarctic Peninsula and southern archipelagos of the Scotia Arc. There is little indication ofrecovery of overexploited fish stocks, and ramifications of fishing activity on bycatch species and the ecosystem could also be far-reaching. The Antarctic Treaty System and its instruments, in particular theConvention for the Conservation of Antarctic Marine Living Resources and the Environmental Protocol, provide a framework within which management of human activities take place. In the face of the
continuing expansion of human activities in Antarctica, a more effective implementation of a wide range of
measures is essential, in order to ensure comprehensive protection of the Antarctic environment, including
its intrinsic, wilderness and scientific values which remains a fundamental principle of the Antarctic Treaty
System. These measures include effective environmental impact assessments, long-term monitoring,
mitigation measures for non-indigenous species, ecosystem-based management of living resources, and
increased regulation of National Antarctic Programmes and tourism activities.

Key words: Antarctic Treaty System, contamination, ecosystem based management, human impacts,
non-indigenous species, tourism


Effects of individual quality, reproductive success and
environmental variability on survival of a long-lived seabird

Amélie Lescroël 1,2 *, Katie M. Dugger 3, Grant Ballard 4,5 and David G. Ainley1
1 H. T. Harvey & Associates, 983 University Avenue, Bldg. D, Los Gatos, CA 95032, USA;
2 CEBC-CNRS, UPR 1934, 79360 Villiers en Bois, France;
3 Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, OR
97331-3803, USA;
4 PRBO Conservation Science, 3820 Cypress Drive #11, Petaluma, CA 94954, USA; and
5 School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand

1. Heterogeneity in individual quality (i.e. individuals having different performance levels that are
consistent throughout life) can drive the demography of iteroparous species, but quality in the
context of environmental variability has rarely been evaluated.
2. We investigated the demographic responses of a long-lived seabird, the Adélie penguin
(Pygoscelis adeliae), to contrasting environmental conditions as a function of reproductive success,
breeding quality (BQ) and experience. A continuous index of BQ (BQI) was developed to reflect an
individual’s ability, relative to others, to produce viable offspring.
3. First, we assessed the relative importance of costs of reproduction vs. heterogeneity in quality by
comparing survival and reproductive probabilities among deferred, successful and unsuccessful
breeders under ‘demanding’ conditions using multistate capture–mark–recapture modelling. Then,
we quantified the influence of BQI on adult survival among experienced breeders vs. the whole
study population under both ‘normal’ and ‘demanding’ conditions.
4. Higher survival rates were exhibited by successful (74–76%) compared to unsuccessful breeders
(64%); the former also more frequently reproduced successfully at year t + 1.
5 .From 1997 to 2006, adult survival ranged from 64–79%, with BQI accounting for 91% of
variability in the entire study population, but only 17% in experienced breeders. The weakened
relationship between BQI and survival in experienced breeders supports the theory that selection
during the first reproductive event accounts for a more homogeneous pool of experienced breeders.
6. No significant effect of environmental covariates on survival was evident, suggesting that what
appeared to be demanding conditions were within the range that could be buffered by this species.
7. For the first time in seabirds, a quadratic relationship between adult survival and BQI showed
that adult survival is shaped by both heterogeneity in quality and reproductive costs. Our study
confirms that population demographic patterns are affected by factors at the individuals’ level
(e.g., individual quality) that are obscured at population-scale levels.

Key-words: costs of reproduction, breeding experience, breeding quality, multistate mark–recapture
models, trade-offs


An energetic correlate between colony size and foraging effort in
seabirds, an example of the Adelie penguin Pygoscelis adeliae

Lisa T. Ballance, David G. Ainley, Grant Ballard and Kerry Barton
L. T. Ballance (correspondence), Southwest Fish. Sci. Center, NOAA Fisheries, 8604 La Jolla Shores Drive, La Jolla, CA 92037, USA. Email:  D. G. Ainley, H.T. Harvey and Associates, 983 University Avenue, Bldg D, Los Gatos CA 95032, USA. 
G. Ballard, PRBO Conserv. Sci., Petaluma, CA 94954, USA and Ecol., Evol. and Behav., School of Biol. Sci., Univ. of Auckland, New
Zealand.  K. Barton, Landcare Res. New Zealand Ltd., Private Bag 6, Nelson, New Zealand.

Abstract: Central-place foraging seabirds alter the availability of their prey around colonies, forming a ‘‘halo’’ of reduced prey access that ultimately constrains population size. This has been indicated indirectly by an inverse correlation between colony size and reproductive success, numbers of conspecifics at other colonies within foraging range, foraging effort (i.e. trip duration), diet quality and colony growth rate. Although ultimately mediated by density dependence relative to food through intraspecific exploitative or interference competition, the proximate mechanism involved has yet to be elucidated. Herein, we show that Ade´lie penguin Pygoscelis adeliae colony size positively correlates to foraging trip duration and metabolic rate, that the metabolic rate while foraging may be approaching an energetic ceiling for birds at the largest colonies, and that total energy expended increases with trip duration although uncompensated by increased mass gain. We propose that a competition-induced reduction in prey availability results in higher energy expenditure for birds foraging in the halo around large colonies, and that to escape the halo a bird must increase its foraging distance. Ultimately, the total energetic cost of a trip determines the maximum successful trip distance, as on longer trips food acquired is used more for self maintenance than for chick provisioning. When the net cost of foraging trips becomes too high, with chicks receiving insufficient food, chick survival suffers and subsequent colony growth is limited. Though the existence of energetic studies of the same species at multiple colonies is rare, because foraging metabolic rate increases with colony size in at least two other seabird species, we suggest that an energetic constraint to colony size may generally
apply to other seabirds.




Ecological repercussions of historical fish extraction
from the Southern Ocean

David G Ainley1 & Louise K Blight2,*
1H.T. Harvey and Associates, 983 University Avenue, Bldg D, Los Gatos, CA 95032, USA; 2Project Seahorse, Fisheries
Centre, University of British Columbia, 2202 Main Mall, Vancouver, BC, Canada V6T 1Z4

Abstract: A major mid-1980s shift in ecological structure of significant portions of the
Southern Ocean was partially due to the serial depletion of fish by intensive industrial
fishing, rather than solely to climate factors as previously hypothesized. Over a brief
period (1969–1973), several finfish stocks were on average reduced to <50%, and
finally (mid-1980s) to <20%, of original size. Despite management actions, few stocks
have recovered and some are still declining. Most affected species exhibit K-selected
life-history patterns, and before exploitation presumably fluctuated in accordance
with infrequent strong year classes, as is true of such fish elsewhere. A climate
regime, the Southern Annular Mode, once oscillated between two states, but has
remained in its ‘positive mode’ since the time of the fish extraction. This may have
increased finfish vulnerability to exploitation. As breeding stocks decreased, we
hypothesize that availability of annually produced juvenile fish fed upon by upperlevel
predators remained low. Correlations between predator populations and fish
biomass in predator foraging areas indicate that southern elephant seal Mirounga
leonina, Antarctic fur seal Arctocephalus gazella, gentoo penguin Pygoscelis papua,
macaroni penguin Eudyptes chrysolphus and ‘imperial’ shag Phalacrocorax spp. – all
feeding extensively on these fish, and monitored at Marion, Crozet, Kerguelen, Heard,
South Georgia, South Orkney and South Shetland Islands, where fishing was
concentrated – declined simultaneously during the two periods of heavy fishing.
These patterns indicate the past importance of demersal fish as prey in Antarctic
marine systems, but determining these interactions’ ecological mechanisms may now
be impossible.



Antarctic Science 19 (3), 283–290 (2007)
Paradigm lost, or is top-down forcing no longer significant in the Antarctic marine ecosystem?


1 H.T. Harvey & Associates, 3150 Almaden Expressway, San Jose, CA 95118, USA
2 PRBO Conservation Science, Bolinas CA 94924 USA; and Ecology, Evolution, and Behaviour,
   School of Biological Sciences, University of Auckland, New Zealand
3 Civil & Environmental Engineering, Clarkson University, Potsdam, NY 13699, USA
4 Aquatic Ecosystems Research Laboratory, University of British Columbia, 2202 Main Mall, Vancouver, BC V6T 1Z4, Canada
5 Biomedical Sciences, Ohio University, Athens, OH 45701, USA
6 Biology and Marine Biology, University of North Carolina, Wilmington, NC 28403, USA
7 Dipartimento Scienze Ambientali, Universita` di Siena, Via Mattioli 4 53100 Siena, Italy
8 709 56th Street, Oakland, CA 94609, USA
9 PO Box 438, West Falmouth, MA 02574, USA
10 17 Modena Crescent, Auckland, New Zealand
11 School of Zoology, University of Tasmania, Sandy Bay, TAS 7000, Australia

Abstract: Investigations in recent years of the ecological structure and processes of the Southern Ocean have almost exclusively taken a bottom-up, forcing-by-physical-processes approach relating various species’ population trends to climate change. Just 20 years ago, however, researchers focused on a broader set of hypotheses, in part formed around a paradigm positing interspecific interactions as central to structuring the ecosystem (forcing by biotic processes, top-down), and particularly on a “krill surplus” caused by the removal from the system of more than a million baleen whales. Since then, this latter idea has disappeared from favour with little debate. Moreover, it recently has been shown that concurrent with whaling there was a massive depletion of finfish in the Southern Ocean, a finding also ignored in deference to climate related explanations of ecosystem change. We present two examples from the literature, one involving gelatinous organisms and the other involving penguins, in which climate has been used to explain species’ population trends but which could better be explained by including species interactions in the modelling. We conclude by questioning the almost complete shift in paradigms that has occurred and discuss whether it is leading Southern Ocean marine ecological science in an instructive direction.




Antarctic Science 19 (1), 31–38 (2007)
Effects of giant icebergs on two emperor penguin colonies in the Ross Sea, Antarctica

1Scholander Hall, Scripps Institution of Oceanography, La Jolla, CA92093-0204, USA
2 H.T. Harvey & Associates, San JoseCA95118, USA
3 PRBO Conservation Science, Bolinas, CA94924, USA
4 Behaviour, School of Biological Sciences, University of Auckland, New Zealand

Abstract: The arrival in January 2001 in the south-west Ross Sea of two giant icebergs, C16 and B15A, subsequently had dramatic effects on two emperor penguin colonies. B15A collided with the north-west tongue of the Ross Ice Shelf at Cape Crozier, Ross Island, in the following months and destroyed the penguins’ nesting habitat. The colony totally failed in 2001, and years after, with the icebergs still in place, exhibited reduced production ranged from 0 to 40% of the 1201 chicks produced in 2000. At Beaufort Island, 70 km NW of Crozier, chick production declined to 6% of the 2000 count by 2004. Collisions with the Ross Ice Shelf at Cape Crozier caused incubating adults to be crushed, trapped in ravines, or to abandon the colony and, since 2001, to occupy poorer habitat. The icebergs separated Beaufort Island from the Ross Sea Polynya, formerly an easy route to feeding and wintering areas. This episode has provided a glimpse of events which have probably occurred infrequently since the West Antarctic Ice Sheet began to retreat 12,000 years ago. The results allow assessment of recovery rates for one colony decimated by both adult and chick mortality, and the other colony by adult abandonment and chick mortality.



From the Columbia University Press

The Adelie Penguin: Bellwether of Climate Change

Dr. David G. Ainley, author

To place an order, go to; or click here.


The Condor 105:95–106 The Cooper Ornithological Society 2003

Spatial and temporal variation of diet within a presumed metapopulation

of Adelie penguins




1H.T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, CA 95118

2Point Reyes Bird Observatory, 4990 Shoreline Highway, Stinson Beach, CA 94970

3Landcare Research New Zealand Ltd., Private Bag 6, Nelson, New Zealand

4Institute of Marine Science, University of California, Santa Cruz, CA 95064

5USGS Wisconsin Cooperative Wildlife Research Unit, Department of Wildlife Ecology,

University of Wisconsin, Madison, WI 53706



Abstract - We investigated temporal and spatial variability in the diet of chick-provisioning

Adelie Penguins (Pygoscelis adeliae) breeding at all colonies within one isolated

cluster in the southwestern Ross Sea, Antarctica, 1994–2000. We wished to determine if

prey quality explained different population growth and emigration rates among colonies.

Diet composition was described both by conventional means (stomach samples) and by

analysis of stable isotopes in chick tissues (toenails of individuals killed by skuas [Stercorarius

maccormicki]). Diets were similar among the four study colonies compared to

the disparity apparent among 14 widely spaced sites around the continent. Calorimetry

indicated that fish are more energetically valuable than krill, implying that if diet varied

by colony, diet quality could attract recruits and help to explain differential rates of colony

growth. However, a multiple-regression analysis indicated that diet varied as a function

of year, time within the year, and percent of foraging area covered by sea ice, but not by

colony location. Stable isotopes revealed similarity of diet at one colony where conventional

sampling was not possible. We confirmed that sea ice importantly affects diet composition

of this species in neritic waters, and found that (1) quality of summer diet cannot

explain different population growth rates among colonies, and (2) stable isotope analysis

of chick tissues (toenails) is a useful tool to synoptically describe diet in this species over

a large area.




Published in Geophysical Research Letters 29(7), 10.1029/2001 GLO, 2002
Ecological Impact of a Large Antarctic Iceberg

Kevin R. Arrigo1, Gert L. van Dijken1, David G. Ainley2, Mark A. Fahnestock3 and Thorsten Markus
1Department of Geophysics, Stanford University, Stanford, CA 94305-21152H. T. Harvey & Associates, San Jose, CA
951183ESSIC, University of Maryland, College Park, MD 20742-24654NASA Goddard Space Flight Center-University of
Maryland Baltimore County Joint Center for Earth Systems Technology (NASA/GSFC- UMBC JCET), Greenbelt, MD 20771

Abstract - Satellite imagery has been used to document for the first time the potential for large icebergs to substantially alter the dynamics of marine ecosystems. The B-15 iceberg, which calved off the Ross Ice Shelf in the biologically productive southwestern Ross Sea, Antarctica, restricted the normal drift of pack ice, resulting in heavier spring/summer pack ice cover than previously recorded. Extensive icecover reduced both the area suitable for phytoplankton growth and the length of the algal growing season. Consequently, primary productivity throughout the region was >40% below normal, changing both the abundance and behavior of upper trophic level organisms.



MARINE ECOLOGY PROGRESS SERIES Mar Ecol Prog Ser Vol. 213: 301–309, 2001 Published April 4
Adélie penguin population change in the pacific sector of Antarctica: relation to sea-ice extent and the Antarctic Circumpolar Current

P. R. Wilson1,*, D. G. Ainley2, N. Nur3, S. S. Jacobs4, K. J. Barton1, G. Ballard2J. C. Comiso5
1Landcare Research, Private Bag 6, Nelson, New Zealand
2H.T. Harvey & Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118, USA
3Point Reyes Bird Observatory, 4990 Shoreline Highway, Stinson Beach, California 94970, USA
4Lamont-Doherty Earth Observatory, Palisades, New York 10964, USA
5Laboratory for Hyrdospheric Processes, NASA-Goddard Space Flight Center, Greenbelt, Maryland 20771, USA

Abstract - One of the longest continuing data sets involving a marine organism in the Antarctic is that of annual estimates of breeding population size of Adélie penguins Pygoscelis adeliae at colonies on Ross Island, Ross Sea, 1959 to 1997. The sizes of these colonies have displayed significant interannual variability during the 29-yr period. We hypothesized that changes are related to natural environmental factors; and used path analysis to analyze annual variation in population growth in relation to physical environmental factors during that part of the record with comparable sea-ice satellite imagery from 1973 to 1997. The Ross Sea sector of the Southern Ocean lying north of Ross Island, from 150° E to 130°W, comprised our study area. Annual population growth measured during summer was explained best, and inversely, by the extent of sea-ice in the study area 5 winters earlier, and in some way related to the Southern Oscillation. Analysis of a subset of the sea-ice data from 1979 to 1997 indicated strong correlations to ice conditions in the eastern portion of the study area (174 to130°W), and virtually no correlations to the western half (150° E to 175° W). This result supported other indirect evidence that the Ross Island penguins winter in the eastern Ross Sea/western Amundsen Sea. A demographic model indicated that variation in survival of juveniles and sub adults mightaccount for the observed population variation, and would also explain the 5-yr lag as 5 yr is the average age of recruitment to the summer breeding population. Extensive sea-ice during winter appears to reduce subadult survival, expressed subsequently when these cohorts reach maturation. We hypothesize that extensive (more northerly) sea-ice limits access of penguins to productive waters known to occur south of the southern boundary of the Antarctic Circumpolar Current, with starvation or increased predation disproportionately affecting less-experienced birds. The observed patterns of penguin population change, including those preceding the satellite era, imply that sea-ice extent has changed significantly over recent decades.





1H.T. Harvey & Associates, 3150 Almaden Expressway, Suite 145, San Jose, CA 95118
2USGS BRD, Department of Wildlife Ecology, University of Wisconsin, Madison, WI 53706
3Landcare Research New Zealand, Ltd., Private Bag 6, Nelson, New Zealand

Abstract -   We compared foraging-trip duration of Adélie Penguins (Pygoscelis adeliae) carrying various combinations of radio-telemetry transmitters; flipper bands; implanted, passively interrogated transponder (PIT) tags; and time-depth recorders at two widely separated colonies of different size on Ross Island, Antarctica, during three austral summers.  Trip duration was measured by electronic devices rather than human observation.  Instrumentation had no significant effect on foraging trip duration.  Most of the variation in foraging trip duration was attributed to individual and year.  Males’ trips were significantly shorter than females’ in a subset of known-sex birds.  No effect was evident in nesting success even for birds that wore instruments for > 20 days.  We recommend use of small, hydrodynamically designed and placed instruments to researchers who wish to collect data unaffected by instrument attachment.

Key words:  foraging, penguin, recorder, radio-transmitter, seabird, sea ice, weighbridge.




Antarctic Science 17 (2), 171–182 (2005) © Antarctic Science Ltd Printed in the UK DOI: 10.1017/S0954102005002567171
Decadal-scale changes in the climate and biota of the
Pacific sector of the Southern Ocean, 1950s to the 1990s

1H.T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, CA95118, USA
2FRS Marine Laboratory, PO Box 101, 375 Victoria Road, AberdeenAB11 9DB, UK
3Department of Geophysics, StanfordUniversity, Stanford, CA94305, USA
4Polar Oceans Research Group, PO Box 368, Sheridan, MT59749, USA
5National Institute of Polar Research, Itabashi, Tokyo 173-8515, Japan
6Landcare Research New Zealand, Private Bag 6, Nelson, New Zealand

Abstract - Simultaneous, but contrary, decadal-scale changes in population trajectories of two penguinspecies in the western Pacific and Ross Sea sectors of the Southern Ocean, during the early/mid-1970s and again during 1988–89, correspond to changes in weather and sea ice patterns. These in turn are related to shifts in the semi-annual and Antarctic oscillations. Populations of the two ecologically dissimilar penguin species - Adélie Pygoscelis adeliae and emperor Aptenodytes forsteri - have been tallied annually since the 1950s making these the longest biological datasets for the Antarctic. Both species are obligates of sea ice and, therefore, allowing for the demographic lags inherent in the response of long-lived species to habitat orenvironmental variation, the proximate mechanisms responsible for the shifts involved changes in coastal wind strength and air and sea temperatures, which in turn affected the seasonal formation and decay of seaice and polynyas. The latter probably affected such rates as the proportion of adults breeding and ultimately the reproductive output of populations in ways consistent with the two species’ opposing sea ice needs.Corresponding patterns for the mid-1970s shift were reflected also in ice-obligate Weddell seal Leptonychotes weddelli populations and the structure of shallow-water sponge communities in the Ross Sea.The 1988–89 shift, by which time many more data sets had become available, was reflected among several ice-frequenting vertebrate species from all Southern Ocean sectors. Therefore, the patterns most clearly identified in the Pacific Sector were apparently spread throughout the high latitudes of the Southern Ocean.




Ecological Monographs, 74(1), 2004, pp. 159–178 2004 by the Ecological Society of America

Geographic structure of Adelie penguin populations:

overlap in colony-specific foraging areas




1H. T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118 USA

2USGS Wisconsin Cooperative Wildlife Research Unit, Department of Wildlife Ecology, University of Wisconsin,

Madison, Wisconsin 53706 USA

3Point Reyes Bird Observatory, Stinson Beach, California 94970 USA

41021 Greenwich Street, San Francisco, California 94904 USA

5LandCare Research New Zealand, Ltd., Private Bag 6, Nelson, New Zealand

6P.O. Box 683, Bolinas, California 94924 USA



Abstract - In an investigation of the factors leading to geographic structuring among

Adelie Penguin (Pygoscelis adeliae) populations, we studied the size and overlap of colony

specific foraging areas within an isolated cluster of colonies. The study area, in the southwestern

Ross Sea, included one large and three smaller colonies, ranging in size from 3900

to 135 000 nesting pairs, clustered on Ross and Beaufort Islands. We used triangulation of

radio signals from transmitters attached to breeding penguins to determine foraging locations

and to define colony-specific foraging areas during the chick-provisioning period of

four breeding seasons, 1997–2000. Colony populations (nesting pairs) were determined

using aerial photography just after egg-laying; reproductive success was estimated by comparing

ground counts of chicks fledged to the number of breeding pairs apparent in aerial

photos. Foraging-trip duration, meal size, and adult body mass were estimated using RFID

(radio frequency identification) tags and an automated reader and weighbridge. Chick

growth was assessed by weekly weighing. We related the following variables to colony

size: foraging distance, area, and duration; reproductive success; chick meal size and growth

rate; and seasonal variation in adult body mass. We found that penguins foraged closest to

their respective colonies, particularly at the smaller colonies. However, as the season progressed,

foraging distance, duration, and area increased noticeably, especially at the largest

colony. The foraging areas of the smaller colonies overlapped broadly, but very little

foraging area overlap existed between the large colony and the smaller colonies, even

though the foraging area of the large colony was well within range of the smaller colonies.

Instead, the foraging areas of the smaller colonies shifted as that of the large colony grew.

Colony size was not related to chick meal size, chick growth, or parental body mass. This

differed from the year previous to the study, when foraging trips of the large colony were

very long, parents lost mass, and chick meals were smaller. In light of existing data on

prey abundance in neritic waters in Antarctica suggesting that krill are relatively evenly

distributed and in high abundance in the Southern Ross Sea, we conclude that penguins

depleted or changed the availability of their prey, that the degree of alteration was a function

of colony size, and that the large colony affected the location (and perhaps ultimately the

size) of foraging areas for the smaller colonies. It appears, therefore, that foraging dynamics

play a role in the geographic structuring of colonies in this species.





Published in Philosophical Transactions of the Royal Society B (2007) 362: 95-111. doi:10.1098/rstb.2006.1956

Trophic interactions within the Ross Sea continental shelf ecosystem

Walker O. Smith Jr1,*, David G. Ainley2 and Riccardo Cattaneo-Vietti3
1Virginia Institute of Marine Sciences, College of William and Mary, Gloucester Point, VA 23062, USA
2H.T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, CA 95118, USA
3Dipartimento per lo Studio del Territorio e delle sue Risorse, Universita` di Genova, Corso Europa 26, 16132 Genova, Italy

Abstract - The continental shelf of the Ross Sea is one of the Antarctic’s most intensively studied regions. We review the available data on the region’s physical characteristics (currents and ice concentrations) and their spatial variations, as well as components of the neritic food web, including lower and middle levels (phytoplankton, zooplankton, krill, fishes), the upper trophic levels (seals, penguins, pelagic birds, whales) and benthic fauna. A hypothetical food web is presented. Biotic interactions, such as the role of Euphausia crystallorophias and Pleuragramma antarcticum as grazers of lower levels and food for higher trophic levels, are suggested as being critical. The neritic food web contrasts dramatically with others in the Antarctic that appear to be structured around the keystone species Euphausia superba. Similarly, we suggest that benthic–pelagic coupling is stronger in the Ross Sea than in most other Antarctic regions.We also highlight many of the unknowns within the food web, and discuss the impacts of a changing Ross Sea habitat on the ecosystem.




Beigel Technology Corporation

PHONE: 760-633-3868

FAX: 760-633-3819






Vol. 262: 19–25, 2003 Published November 7

Late-Holocene initiation of ice-free ecosystems

in the Southern Ross Sea, Antarctica


Steven D. Emslie1,*, Paul Arthur Berkman2, David G. Ainley3, Larry Coats4,

Michael Polito1

1Department of Biological Sciences, University of North Carolina, 601 S. College Road, Wilmington, North Carolina 28403, USA

2Byrd Polar Research Center, Ohio State University, 1090 Carmack Road, Columbus, Ohio 43210, USA

3H. T. Harvey & Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118, USA

4Quaternary Sciences Program, Department of Geology, Northern Arizona University, Flagstaff, Arizona 86011, USA



Abstract - New data on marine sediments, seawater paleotemperatures, and the occupation history of Adélie penguins indicate that modern ice-free conditions in the southern Ross Sea developed only within the last 1000 yr. Here we show that penguins permanently abandoned the southern Victoria Land Coast 2000 yr ago when extensive sea-ice cover blocked access to ice-free terrain for breeding. The first colonization of Ross Island in East McMurdo Sound, where over 300 000 penguins breed today, did not commence until after 1170 yr BP when coastal areas became exposed from under the Ross Ice Shelf. Our results demonstrate that investigations of abandoned penguin colonies can provide increased resolution to Holocene paleoclimatic records and paleoceanographic conditions in Antarctica.





Antarctic Science 17 (3), 385–386 (2005) © Antarctic Science Ltd Printed in the UK

DOI: 10.1017/S0954102005002828385

Short Note:

Killer whale harassment of Adélie penguins at Ross Island



1 PRBO Conservation Science, 4990 Shoreline Highway 1, Stinson Beach, CA 94970 USA

2H.T. Harvey & Associates, 3150 Almaden Expressway, Suite 145, San Jose CA 95118 USA

Received 16 December 2004, accepted 15 March 2005





Antarctic Science 17 (3), 335–340 (2005) © Antarctic Science Ltd Printed in the UK

DOI: 10.1017/S0954102005002750335

Leopard seal predation rates at penguin colonies of different size



1H.T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, CA 95118 USA

2PRBO Conservation Science, 4990 Shoreline Highway, Stinson Beach, CA 94970, USA

3Landcare Research New Zealand, Private Bag 6, Nelson, New Zealand

4Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, OR 97331-3803, USA




Abstract -  In a study designed to elucidate the factors that might differentially affect the well being and biology of Adélie penguins (Pygoscelis adeliae) that breed in colonies of different size, we investigated the predation rates on penguins by leopard seals (Hydrurga leptonyx) over a period of six years. The study colonies varied in size across the full range for this penguin species, contrasting with previous studies in which data were gathered only at very large colonies, and only in single years. The number of seals present varied directly with the amount of penguin traffic in the areas near the beach, where most predation takes place. Seals were present persistently only when penguin traffic exceeded about 250 penguins per hour. Predation rates also varied with penguin traffic in a curvilinear fashion, leveling off where traffic exceeded about 1200 penguins per hour. With respect to predation, it appears to be advantageous for Adélie penguins to nest in very small or very large colonies. At large colonies, the number of penguins moving to and from the colony ‘swamp’ the seals’ predatory efforts, thus reducing the chances that an individual penguin will be taken. Small colonies are of little interest to the seals.

Received 16 December 2004, accepted 21 March 2005





Effects of flipper bands on foraging behavior and survival of

Adelie penguins (pygoscelis adeliae)


KM.D1,5 GB2 DGA,3 KJB4

1Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, Oregon 97331, USA;

2PRBO Conservation Science, 4900 Shoreline Highway, Stinson Beach, California 94970, USA;

3H. T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118, USA; and

4Landcare Research, Private Bag 6, Nelson, New Zealand



Abstract - Since the 1950s, flipper bands have been used widely to mark penguins

(Spheniscidae), but not without concerns regarding possible negative effects

on survival and fitness. As part of a demographic study of Adélie Penguins (Pygoscelis

adeliae) in the western Ross Sea, Antarctica, we investigated effects of flipper bands

on foraging-trip duration and food loads, as well as apparent survival, during four

breeding seasons (2000–2003), using mark–recapture and radio-frequency identification

(RFID) technology. Foraging-trip durations were ~8% (3.5 h) longer, on

average, for banded compared with unbanded birds, but the effect varied among

years. Food loads did not differ between banded and unbanded birds, but males

carried heavier food loads than females. Flipper bands decreased apparent annual

survival by 11–13% during 2000–2003, but over a longer time period (1996–2003) we

observed high annual variability, including years of high survival for banded birds.

Males had slightly higher survival than females in both banded and unbanded birds.

Mechanisms resulting in band effects on foraging behavior and survival, the variable

effect of bands by season, and the potential ameliorating effect of age or experience

on the effects of bands need further investigation in Adélie and other penguin

species. We recognize a need to understand and balance the negative consequences

of flipper bands for penguins against the beneficial gains in information associated

with their use. Received 5 January 2005, accepted 14 October 2005.





Ecology, 87(8), 2006, pp. 2080–2093 2006 by the the Ecological Society of America

Competition among penguins and cetaceans reveals trophic cascades in the Western Ross Sea, Antarctica



1H. T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118 USA

2PRBO Conservation Science, P.O. Box 1157, Bolinas, California 94924 USA, and Ecology, Evolution and Behaviour,

School of Biological Sciences, University of Auckland, New Zealand

3Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, Oregon 97331 USA



Abstract - An apparent trophic cascade that appears during summer in the western Ross

Sea, Antarctica, explains why the Antarctic silverfish (Pleuragramma antarcticum) there

becomes cannibalistic; its principal prey, crystal krill (Euphausia crystallorophias) becomes

scarce; and the diatom community is minimally grazed compared to adjacent areas. The krill is

the major grazer of diatoms. On the basis of fieldwork at Ross Island, we suggest that the

cascade results from foraging by unusually numerous Adelie Penguins (Pygoscelis adeliae),

minke whales (Balaenoptera bonaerensis), and fish-eating killer whales (Orcinus orca). These

species and other top predators apparently deplete the krill and silverfish. In drawing our

conclusions, we were aided by two ‘‘natural experiments.’’ In one ‘‘experiment,’’ large,

grounded icebergs altered the seasonal pattern of change in regional sea-ice cover, but not the

seasonal change in penguin diet and foraging behavior that was also detected during the preiceberg era. In the other ‘‘experiment,’’ a short-term polynya (opening in the ice) brought

penguins and whales together in a confined area, this time altering both penguin diet and

foraging behavior. We conclude that the foraging of penguins and whales, and not a formerly

hypothesized seasonal decrease in sea-ice cover, explains (1) the annual switch in the penguins’

prey from krill to silverfish, (2) the subsequent lengthening of penguin foraging trips, and (3) a

marked decline of cetaceans in the area later in the season. Reduction in the middle-trophic level

prey is expressed in the relaxed grazing pressure on phytoplankton.





Microevolution and mega-icebergs in the Antarctic


L. D. Shepherd*, C. D. Millar†, G. Ballard‡, D. G. Ainley§, P. R. Wilson¶, G. D. Haynes*, C. Baroni_, and D. M. Lambert*,**

*Allan Wilson Centre for Molecular Ecology and Evolution, Institute of Molecular BioSciences, Massey University, Private Bag 102904, NSMC, Albany, Auckland, New Zealand; †Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand; ‡Point Reyes Bird Observatory Conservation Science, Stinson Beach, CA 94970; §H. T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, CA 95118; ¶LandCare Research New Zealand Ltd., Private Bag 6, Nelson, New Zealand; and _Dipartimento Scienze della Terra, Universita` di Pisa, and Consiglio Nazionale Ricerche, Institute of Geoscience and Earth Resources, Via Santa Maria 53, 56126 Pisa, Italy Edited by Tomoko Ohta, National Institute of Genetics, Mishima, Japan, and approved September 21, 2005 (received for review March 20, 2005)



Abstract - Microevolution is regarded as changes in the frequencies of genes in populations over time. Ancient DNA technology now provides an opportunity to demonstrate evolution over a geological time frame and to possibly identify the causal factors in any such evolutionary event. Using nine nuclear micro satellite DNA loci, we genotyped an ancient population of Adelie penguins (Pygoscelis adeliae) aged _6,000 years B.P. Sub fossil bones from this population were excavated by using an accurate stratigraphic method that allowed the identification of individuals even within the same layer. We compared the allele frequencies in the ancient population with those recorded from the modern population at the same site in Antarctica. We report significant changes in the frequencies of alleles between these two time points, hence demonstrating micro evolutionary change. This study demonstrates a nuclear gene-frequency change over such a geological time frame. We discuss the possible causes of such a change, including the role of mutation, genetic drift, and the effects of gene mixing among different penguin populations. The latter is likely to be precipitated by mega-icebergs that act to promote migration among penguin colonies that typically show strong natal return.