scholarly journals Regional Differences in the Diets of Adélie and Emperor Penguins in the Ross Sea, Antarctica

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2681
Author(s):  
Seo-Yeon Hong ◽  
Jong-Ku Gal ◽  
Bo-Yeon Lee ◽  
Wu-Ju Son ◽  
Jin-Woo Jung ◽  
...  

To identify the dietary composition and characteristics of both Adélie (Pygoscelis adeliae) and Emperor (Aptenodytes forsteri) penguins at four breeding sites, we performed stable carbon (δ13C) and nitrogen (δ15N) isotope analysis of down samples taken from penguin chicks. Adélie Penguin chicks at Cape Hallett mostly fed on Antarctic krill (Euphausia superba; 65.5 ± 3.5%), a reflection of the prevalence of that species near Cape Hallett, and no significant differences were noted between 2017 and 2018. However, Adélie Penguin chicks at Inexpressible Island, located near Terra Nova Bay, fed on both Antarctic silverfish (Pleuragramma antarctica; 42.5%) and ice krill (Euphausia crystallorophias; 47%), reflecting the high biomass observed in Terra Nova Bay. Meanwhile, no significant difference was noted between the two breeding sites of the Emperor Penguin. Emperor Penguin chicks predominantly fed on Antarctic silverfish (74.5 ± 2.1%) at both breeding sites (Cape Washington and Coulman Island), suggesting that diet preference represents the main factor influencing Emperor Penguin foraging. In contrast, the diet of the Adélie Penguin reflects presumed regional differences in prey prevalence, as inferred from available survey data.

Polar Record ◽  
2007 ◽  
Vol 43 (3) ◽  
pp. 225-229 ◽  
Author(s):  
Matthew Low ◽  
Lisa Meyer ◽  
Colin Southwell

ABSTRACTIn November 2005, the first comprehensive survey for Adélie penguin (Pygoscelis adeliae) breeding sites in the Robinson Group of islands, situated 25 to 55 km east of Australia's Mawson station (67.602°S, 62.879°E) was conducted. Breeding Adélie penguins were found on 30 of the 149 islands, with the number of nests on each island ranging from fewer than 10 to several thousand. With the exception of those islands in the southeast, nesting Adélie penguins were found throughout the Robinson Group. In this paper, the spatial coordinates and presence/absence of breeding penguins for all 149 islands are reported so that researchers may interpret the results in relation to possible future survey work. All locations reported in this paper are in decimal degrees.


Polar Record ◽  
2000 ◽  
Vol 36 (198) ◽  
pp. 215-232 ◽  
Author(s):  
F.I. Norman

AbstractTemporally and spatially increasing information on the distribution of Adélie penguin (Pygoscelis adeliae) breeding sites is used as an index of various national activities in eastern Prydz Bay, East Antarctica. Recorded instances of such sites are used to indicate both exploration and enhanced local knowledge. While Norwegians discovered the area (1935), and revisited it (1937), reports of penguins were minimal. The 1938 Ellsworth expedition added few details and the potential of Operation Highjump (1947) photographs to delimit breeding sites was never realised. Observations by Australian expeditioners from the mid-1950s onwards, supplemented to some extent by those from the Soviet Union, increased information substantially. When Davis station was established (January 1957), at least five breeding sites were known around eastern Prydz Bay. By 1973 this had increased to 23 or 24 sites, mostly north of the Sørsdal Glacier, which had apparently acted as a barrier to land-based exploration. Data available to 1980 showed 20 sites in the Vestfold Hills, added two in the Rauer Group, and omitted some recorded earlier. Ground surveys of the Vestfold Hills (November 1973) increased known sites slightly, discounted erroneous records, and massively increased numbers of individual colonies. In 1981 an air survey recognised 24 sites in the Vestfold Hills and increased those known to 47. In approximately the same period, official Soviet records showed perhaps four sites in the Vestfold Hills and another in the Rauer Group. Early reports provided poor estimates of breeding population sizes — totals of some 130,000 (or 174,200) pairs in the Vestfold Hills in 1973 are compared with perhaps 196,600 in 1981, with another 129,000 pairs to the south. By 1983 locations of breeding sites in the Vestfold Hills were well established, and this was achieved in southern Prydz Bay following publication of 1981 survey results.Progression of information regarding breeding sites in eastern Prydz Bay was slow. Initial Australian activities were slight following acceptance of its Antarctic Territory (1933). However, a Soviet Antarctic whaling fleet, uncertainty regarding American and Soviet intentions, and the imminent International Geophysical Year increased Australian interest. A station was established, local search areas expanded, and enhanced details regarding penguin breeding sites and colonies followed. Data reviews and surveys followed increasing international interest in southern ecosystems. Improved knowledge regarding the species' local populations reflected changing political agendas. Indeed, ‘knowledge’ itself gave early support to territorial claims. Participation in international surveys became an acceptable scientific endeavour, anticipated under Treaty agreements and promoted by associated organisations. In such fora, surveys and monitoring are expected, although not necessarily furthering the strength of existing claims.


Geology ◽  
2020 ◽  
Author(s):  
Steven D. Emslie

The Ross Sea (Antarctica) is one of the most productive marine ecosystems in the Southern Ocean and supports nearly one million breeding pairs of Adélie penguins (Pygoscelis adeliae) annually. There also is a well-preserved record of abandoned penguin colonies that date from before the Last Glacial Maximum (>45,000 14C yr B.P.) through the Holocene. Cape Irizar is a rocky cape located just south of the Drygalski Ice Tongue on the Scott Coast. In January 2016, several abandoned Adélie penguin sites and abundant surface remains of penguin bones, feathers, and carcasses that appeared to be fresh were being exposed by melting snow and were sampled for radiocarbon analysis. The results indicate the “fresh” remains are actually ancient and that three periods of occupation by Adélie penguins are represented beginning ca. 5000 calibrated calendar (cal.) yr B.P., with the last occupation ending by ca. 800 cal. yr B.P. The presence of fresh-appearing remains on the surface that are actually ancient in age suggests that only recently has snowmelt exposed previously frozen carcasses and other remains for the first time in ~800 yr, allowing them to decay and appear fresh. Recent warming trends and historical satellite imagery (Landsat) showing decreasing snow cover on the cape since 2013 support this hypothesis. Increased δ13C values of penguin bone collagen further indicate a period of enhanced marine productivity during the penguin “optimum”, a warm period at 4000–2000 cal. yr B.P., perhaps related to an expansion of the Terra Nova Bay polynya with calving events of the Drygalski Ice Tongue.


Polar Biology ◽  
2021 ◽  
Author(s):  
Vahideh Jafari ◽  
Deborah Maccapan ◽  
Giulio Careddu ◽  
Simona Sporta Caputi ◽  
Edoardo Calizza ◽  
...  

AbstractThe Ross Sea, Antarctica, supports large populations of Emperor Penguin (Aptenodytes forsteri) and Adélie Penguin (Pygoscelis adeliae), two key meso-predators that occupy high trophic levels. Despite these species are largely studied, little is known about their diet outside the breeding period. In the present study, we investigated the intra-annual diet of Adélie and Emperor Penguins belonging to five colonies in the Ross Sea through the stable isotope analysis of different tissues (feathers and shell membranes), synthetized in different seasons, and guano that indicates recent diet. Penguin samples and prey (krill and fish) were collected during the Antarctic spring–summer. δ13C and δ15N of tissues and guano indicate spatio-temporal variation in the penguin diet. The krill consumption by Adélie Penguins was lowest in winter except in the northernmost colony, where it was always very high. It peaked in spring and remained prevalent in summer. The greatest krill contribution to Emperor Penguin’s diet occurred in summer. The relative krill and fish consumption by both species changed in relation to the prey availability, which is influenced by seasonal sea ice dynamics, and according to the penguin life cycle phases. The results highlight a strong trophic plasticity in the Adélie Penguin, whose dietary variability has been already recognized, and in the Emperor Penguin, which had not previously reported. Our findings can help understand how these species might react to resource variation due to climate change or anthropogenic overexploitation. Furthermore, data provides useful basis for future comparisons in the Ross Sea MPA and for planning conservation actions.


The Holocene ◽  
2011 ◽  
Vol 22 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Sandra Lorenzini ◽  
Ilaria Baneschi ◽  
Anthony E. Fallick ◽  
Maria Cristina Salvatore ◽  
Giovanni Zanchetta ◽  
...  

2002 ◽  
Vol 14 (4) ◽  
pp. 327-332 ◽  
Author(s):  
MICHAEL POLITO ◽  
STEVEN D. EMSLIE ◽  
WILLIAM WALKER

Non-krill prey remains were recovered from ornithogenic sediments at three active Adélie penguin colonies on Ross Island, to assess long-term dietary trends in this species. Radiocarbon dates place the age of these deposits from a maximum of 947 years ago to the present. We identified 12 taxa of fish and two of squid with the Antarctic silverfish (Pleuragramma antarcticum) as the most abundant prey species represented at all sites. In addition, silverfish have decreased in importance in Adélie penguin diet over the past 600 years, perhaps in response to climate change since the onset of the Little Ice Age, though it remains much more abundant in current penguin diet in the Ross Sea than in the Antarctic Peninsula. Other prey taxa reflect the diversity of prey selection by Adélie penguins in Antarctica.


2008 ◽  
Vol 295 (5) ◽  
pp. R1671-R1679 ◽  
Author(s):  
Mireille Raccurt ◽  
Fannie Baudimont ◽  
Julien Tirard ◽  
Benjamin Rey ◽  
Elodie Moureaux ◽  
...  

Rapid growth is of crucial importance for Adélie penguin chicks reared during the short Antarctic summer. It partly depends on the rapid ontogenesis of fat stores that are virtually null at hatching but then develop considerably (×40) within a month to constitute both an isolative layer against cold and an energy store to fuel thermogenic and growth processes. The present study was aimed at identifying by RT-PCR the major transcriptional events that chronologically underlie the morphological transformation of adipocyte precursors into mature adipocytes from hatching to 30 days of age. The peak expression of GATA binding protein 3, a marker of preadipocytes, at day 7 posthatch indicates a key proliferation step, possibly in relation to the expression of C/EBPα (C/EBPα). High plasma total 3,5,3′-triiodo-l-thyronine (T3) levels and high levels of growth hormone receptor transcripts at hatching suggested that growth hormone and T3 play early activating roles to favor proliferation of preadipocyte precursors. Differentiation and growth of preadipocytes may occur around day 15 in connection with increased abundance of transcripts encoding IGF-1, proliferator-activated receptor-γ, and C/EBPβ, gradually leading to functional maturation of metabolic features of adipocytes including lipid uptake and storage (lipoprotein lipase, fatty-acid synthase) and late endocrine functions (adiponectin) by day 30. Present results show a close correlation between adipose tissue development and chick biology and a difference in the scheduled expression of regulatory factors controlling adipogenesis compared with in vitro studies using cell lines emphasizing the importance of in vivo approaches.


2005 ◽  
Vol 17 (1) ◽  
pp. 57-66 ◽  
Author(s):  
STEVEN D. EMSLIE ◽  
ERIC J. WOEHLER

We investigated 17 abandoned Adélie penguin (Pygoscelis adeliae) colonies in the Windmill Islands, East Antarctica, in summer 2002/03. Forty radiocarbon dates on penguin bones and eggshells from 13 of these sites indicate a near continuous occupation by breeding penguins in this region for over 9000 years. These dates refine the recent geological record in this region and indicate that deglaciation of the northern islands occurred much earlier than previously suggested. Dietary remains from these sites include at least 23 taxa of cephalopods and teleost fish. Quantification of these remains indicates significant fluctuations in the relative abundance of two of the more common major prey taxa. The Antarctic silverfish (Pleuragramma antarcticum Boulenger) was the most common teleost prey during all time periods represented by the ages of the sites, but preservational factors may explain a gradual decrease in the remains of this species in increasingly older sites. The most common cephalopod in the sediments was the squid, Psychroteuthis glacialis Thiele, which occurred in low numbers in most sites except one (Site 75). An unusually high number of squid beaks preserved in Site 75, dating to approximately 5700–6100 cal. yr BP, does not correlate with a decrease in fish prey at that time. The high number of abandoned penguin colonies (> 200) in the Windmill Islands may be due to population cycles in the past in association with low nest-site fidelity and movement by breeding penguins to new sites within this region.


2013 ◽  
Vol 305 (9) ◽  
pp. R1065-R1075 ◽  
Author(s):  
Anaïs Fongy ◽  
Caroline Romestaing ◽  
Coralie Blanc ◽  
Nicolas Lacoste-Garanger ◽  
Jean-Louis Rouanet ◽  
...  

The ontogeny of pectoralis muscle bioenergetics was studied in growing Adélie penguin chicks during the first month after hatching and compared with adults using permeabilized fibers and isolated mitochondria. With pyruvate-malate-succinate or palmitoyl-carnitine as substrates, permeabilized fiber respiration markedly increased during chick growth (3-fold) and further rose in adults (1.4-fold). Several markers of muscle fiber oxidative activity (cytochrome oxidase, citrate synthase, hydroxyl-acyl-CoA dehydrogenase) increased 6- to 19-fold with age together with large rises in intermyofibrillar (IMF) and subsarcolemmal (SS) mitochondrial content (3- to 5-fold) and oxidative activities (1.5- to 2.4-fold). The proportion of IMF relative to SS mitochondria increased with chick age but markedly dropped in adults. Differences in oxidative activity between mitochondrial fractions were reduced in adults compared with hatched chicks. Extrapolation of mitochondrial to muscle respirations revealed similar figures with isolated mitochondria and permeabilized fibers with carbohydrate-derived but not with lipid-derived substrates, suggesting diffusion limitations of lipid substrates with permeabilized fibers. Two immunoreactive fusion proteins, mitofusin 2 (Mfn2) and optic atrophy 1 (OPA1), were detected by Western blots on mitochondrial extracts and their relative abundance increased with age. Muscle fiber respiration was positively related with Mfn2 and OPA1 relative abundance. Present data showed by two complementary techniques large ontogenic increases in muscle oxidative activity that may enable birds to face thermal emancipation and growth in childhood and marine life in adulthood. The concomitant rise in mitochondrial fusion protein abundance suggests a role of mitochondrial networks in the skeletal muscle processes of bioenergetics that enable penguins to overcome harsh environmental constraints.


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