- Adelie penguin survival: age structure, temporal variability and environmental influences
Louise Emmerson and Colin Southwell.
Oecologia, Vol. 167, No. 4, Dec 2011, pp. 951-65.
The driving factors of survival, a key demographic process, have been particularly challenging to study, especially for winter migratory species such as the Adélie penguin (Pygoscelis adeliae). While winter environmental conditions clearly influence Antarctic seabird survival, it has been unclear to which environmental features they are most likely to respond. Here, we examine the influence of environmental fluctuations, broad climatic conditions and the success of the breeding season prior to winter on annual survival of an Adélie penguin population using mark-recapture models based on penguin tag and resight data over a 16-year period. This analysis required an extension to the basic Cormack-Jolly-Seber model by incorporating age structure in recapture and survival sub-models. By including model covariates, we show that survival of older penguins is primarily related to the amount and concentration of ice present in their winter foraging grounds. In contrast, fledgling and yearling survival depended on other factors in addition to the physical marine environment and outcomes of the previous breeding season, but we were unable to determine what these were. The relationship between sea-ice and survival differed with penguin age: extensive ice during the return journey to breeding colonies was detrimental to survival for the younger penguins, whereas either too little or too much ice (between 15 and 80% cover) in the winter foraging grounds was detrimental for adults. Our results demonstrate that predictions of Adélie penguin survival can be improved by taking into account penguin age, prior breeding conditions and environmental features.[PUBLICATION ABSTRACT]
- Penguin heat-retention structures evolved in a greenhouse Earth
Daniel B. Thomas, Daniel T. Ksepka and REwan Fordyce.
Biology Letters, Vol. 7, No. 3, Jun 23, 2011, pp. 461-464.
Penguins (Sphenisciformes) inhabit some of the most extreme environments on Earth. The 60+ Myr fossil record of penguins spans an interval that witnessed dramatic shifts in Cenozoic ocean temperatures and currents, indicating a long interplay between penguin evolution and environmental change. Perhaps the most celebrated example is the successful Late Cenozoic invasion of glacial environments by crown clade penguins. A major adaptation that allows penguins to forage in cold water is the humeral arterial plexus, a vascular counter-current heat exchanger (CCHE) that limits heat loss through the flipper. Fossil evidence reveals that the humeral plexus arose at least 49 Ma during a 'Greenhouse Earth' interval. The evolution of the CCHE is therefore unrelated to global cooling or development of polar ice sheets, but probably represents an adaptation to foraging in subsurface waters at temperate latitudes. As global climate cooled, the CCHE was key to invasion of thermally more demanding environments associated with Antarctic ice sheets.
- Turning the world upside down
Edward J. Larson.
Nature, Vol. 480, No. 7375, Dec 1, 2011, pp. 29-31.
FIRST STEPS Commanded by geophysicist Erich von Drygalski, the Gauss left Germany in the summer of 1901. Besting the researchers on the Discovery expedition on virtually every score, they determined that Antarctica is a continental landmass, plotted the atmospheric patterns radiating from the South Polar Region, found widespread evidence of retreating glaciers, discovered freshwater algae and microorganisms in frozen lakes, and obtained fossil evidence of higher plant life in a land now devoid of it.
- ECOLOGICAL CORRELATES OF MICROFILARIAE PREVALENCE IN ENDANGERED GALÁPAGOS BIRDS
Shane Siers, Jane Merkel, Arnaud BatailIe, F. H. Vargas and P. G. Parker.
The Journal of parasitology, Vol. 96, No. 2, Apr 2010, pp. 259-72.
This study assesses the ecological factors associated with microfilariae prevalence in wild populations of endangered flightless cormorants (Phalacrocorax harrisi) and Galápagos penguins (Spheniscus mendiculus). Prevalence values were tested for correlation with a large number of environmental variables, as modeled from weather station data and measured by satellite-borne sensors. Predictions were made based on the expected effects of climatic and landscape variables on sustained populations of arthropod vectors required for transmission of microfilariae. In general, findings were consistent with predictions in both cormorants and penguins; prevalence correlated positively with temperature, precipitation, and vegetation density, and negatively with measures of environmental variability. Resulting correlates were used to derive predictive distributions of prevalence values in cormorants throughout the archipelago. Evidence is presented implicating the mosquito Aedes taeniorhynchus as a likely vector. Knowledge of environmental variables that predict risk of disease transmission by arthropod vectors may be useful in control measures should novel pathogens be introduced to the ecosystem.
- Is marine debris ingestion still a problem for the coastal marine biota of southern Brazil?
Paula S. Tourinho, Juliana A. Ivar do Sul and Gilberto Fillmann.
Marine pollution bulletin, Vol. 60, No. 3, Mar 2010, pp. 396-401.
The accumulation of synthetic debris in marine and coastal environments is a consequence of the intensive and continuous release of these highly persistent materials. This study investigates the current status of marine debris ingestion by sea turtles and seabirds found along the southern Brazilian coast. All green turtles (n=34) and 40% of the seabirds (14 of 35) were found to have ingested debris. No correlation was found between the number of ingested items and turtle's size or weight. Most items were found in the intestine. Plastic was the main ingested material. Twelve Procellariiformes (66%), two Sphenisciformes (22%), but none of the eight Charadriiformes were found to be contaminated. Procellariiformes ingested the majority of items. Plastic was also the main ingested material. The ingestion of debris by turtles is probably an increasing problem on southern Brazilian coast. Seabirds feeding by diverse methods are contaminated, highlighting plastic hazard to these biota.
- Effects of Pollution on Marine Organisms
Alan J. Mearns, Donald J. Reish, Philip S. Oshida, Michael Buchman, Thomas Ginn and Robert Donnelly.
Water Environment Research, Vol. 81, No. 10, 2009, pp. 2070-2125.
This review covers selected 2008 peer-reviewed journal articles on the biological, chemical and physical effects of natural and anthropogenic disturbances on marine and estuarine plants and animals. The first five sections cover reviews and field and laboratory measurement activities (concentrations of contaminants, field surveys, toxicity testing and biomarkers). The last six sections focus further on pollution issues of current interest including endocrine disrupters, vessel and marine coatings, ballast water treatment, marine debris, oil spills, wastewater discharges, dredging and disposal, etc. There is considerable overlap across subject areas (e.g. some organotin papers may be cited in the biomarker section). As always, readers should only use this as a guide and must consult the original papers before citing them, including double-checking units. [PUBLICATION ABSTRACT]
- Penguin responses to climate change in the Southern Ocean
Jaume Forcada and Philip N. Trathan.
Global Change Biology, Vol. 15, No. 7, Jul 2009, pp. 1618-1630.
AbstractPenguins are adapted to live in extreme environments, but they can be highly sensitive to climate change, which disrupts penguin life history strategies when it alters the weather, oceanography and critical habitats. For example, in the southwest Atlantic, the distributional range of the ice-obligate emperor and Adelie penguins has shifted poleward and contracted, while the ice-intolerant gentoo and chinstrap penguins have expanded their range southward. In the Southern Ocean, the El Nino-Southern Oscillation and the Southern Annular Mode are the main modes of climate variability that drive changes in the marine ecosystem, ultimately affecting penguins. The interaction between these modes is complex and changes over time, so that penguin responses to climate change are expected to vary accordingly, complicating our understanding of their future population processes. Penguins have long life spans, which slow microevolution, and which is unlikely to increase their tolerance to rapid warming. Therefore, in order that penguins may continue to exploit their transformed ecological niche and maintain their current distributional ranges, they must possess adequate phenotypic plasticity. However, past species-specific adaptations also constrain potential changes in phenology, and are unlikely to be adaptive for altered climatic conditions. Thus, the paleoecological record suggests that penguins are more likely to respond by dispersal rather than adaptation. Ecosystem changes are potentially most important at the borders of current geographic distributions, where penguins operate at the limits of their tolerance; species with low adaptability, particularly the ice-obligates, may therefore be more affected by their need to disperse in response to climate and may struggle to colonize new habitats. While future sea-ice contraction around Antarctica is likely to continue affecting the ice-obligate penguins, understanding the responses of the ice-intolerant penguins also depends on changes in climate mode periodicities and interactions, which to date remain difficult to reproduce in general circulation models.
- Anchovy Fishery Threat to Patagonian Ecosystem
Elizabeth Skewgar, PDee Boersma, Graham Harris and Guillermo Caille.
Science (Washington), Vol. 315, No. 5808, Jan 5, 2007, pp. 45.
The Patagonian coast is famous for its charismatic megafauna—Magellanic penguins, southern right whales, southern elephant seals, and southern sea lions--but the small, less charismatic southwest Atlantic anchovy is a key trophic link in the ecosystem. Overfishing anchovy could disrupt energy flows in the southwest Atlantic ecosystem, harm other fisheries and wildlife, and damage the valuable ecotourism sector.
- Influence of chlorophyll and sea ice dynamics on the reproduction and recruitment of the Antarctic krill Euphausia superba in waters west of the Antarctic Peninsula (45-75 degree S, 50-80 degree W)
M. Marrari, K. L. Daly and C. Hu.
4. Int. Zooplankton Production Symp., Hiroshima (Japan), 28 May-1 Jun 2007
The reproductive patterns and recruitment success of the Antarctic krill Euphausia superba were investigated in relation to chlorophyll distributions and sea ice dynamics in waters west of the Antarctic Peninsula during 2000/2001 and 2001/2002 as part of the Southern Ocean GLOBEC programme. The Antarctic Peninsula is warming relative to other regions of the Southern Ocean, potentially impacting on phytoplankton populations and consequently on krill, which in turn may have an effect on top predators such as whales, seals, and penguins. Climatological SeaWiFS chlorophyll data (1997-2004) showed that the Bellingshausen Sea and Marguerite Bay regions consistently had higher and more persistent chlorophyll concentrations than the more northern areas along the Antarctic Peninsula shelf and the western Scotia Sea. Net and high-frequency acoustic data revealed strong interannual variability in krill abundance and population structure. Unusually high krill reproduction in 2000/2001 coincided with widespread high positive chlorophyll anomalies and resulted in a relatively large juvenile recruitment during the following spring. Ice edge blooms were only a significant feature in the Bellingshausen Sea and, thus, were not likely to support krill reproduction in the northern Peninsula region. Differences in sea ice conditions in Marguerite Bay during spring and summer also probably contributed to the variable krill abundances observed. Winter sea ice cover was extensive during both seasons. Thus, above average chlorophyll concentrations and favourable sea ice conditions in coastal areas during spring and summer 2000/2001 likely supported the high densities of larval krill observed during fall in waters west of the Antarctic Peninsula.
- Modelling and mapping resource overlap between seabirds and fisheries on a global scale: a preliminary assessment
Vasiliki S. Karpouzi, Reg Watson and Daniel Pauly.
Marine Ecology Progress Series, Vol. 343, Aug 2007, pp. 87-99.
Coexistence of foraging seabirds and operating fisheries may result in interactions such as competition for the same prey resources. We used GIS- based modelling at a scale of 0.5 x 0.5 degree spatial cells to: (1) map the foraging distribution of seabirds; (2) predict their annual food consumption rates in a spatially explicit manner; and (3) estimate a spatially explicit seabird-fisheries overlap index. Information on population size, diet composition and foraging attributes of 351 seabird species was compiled into a Microsoft Access database. Global annual food consumption by seabirds was estimated to be 96.4 million tonnes (95% CI: 78.0 to 114.7 million tonnes), compared with a total catch of nearly 120 million tonnes by all marine fisheries. Krill and cephalopods comprised over 58% of the overall food consumed and fish most of the remainder. The families Procellariidae (albatrosses, petrels, shearwaters) and Spheniscidae (penguins) were responsible for over 54% of the overall food consumption. Seabird foraging distribution maps revealed that areas around New Zealand, the eastern Australian coast, and the sub-Antarctic islands had high species richness. However, temperate and polar regions supported high seabird densities and most food extracted by seabirds originated there. Furthermore, maps of food consumption rates revealed that most food consumed by seabirds was extracted from offshore rather than nearshore waters and from areas where seabird- fisheries overlap was low. The resource overlap maps identified 'hotspots' of highest potential for conflict between fisheries and seabirds. Thus, this study may provide useful insight when developing management approaches for designing offshore marine conservation areas.
- Modelling the Effect of El Nino on the Persistence of Small Populations: The Galapagos Penguin as a Case Study
FHernan Vargas, Robert C. Lacy, Paul J. Johnson, et al.
Biological Conservation, Vol. 137, No. 1, Jun 2007, pp. 138.
The effects of El Nino on the persistence of small populations of Galapagos penguin were modeled. A baseline model of the current effect of El Nino events on the penguin populations was built using frequencies of the events, and conducting sensitivity analyses of the effects of past and future El Nino events and estimating the minimum viable population (MVP) size for the population. Penguins did not nest, and probably expanded their foraging areas, during strong El Nino events. It was observed that a lower detectability of birds would account for part of the large declines recorded during the strong 1982-83 and 1997-98 El Nino events. Frequency of El Nino events between 1965 and 2004 indicated 30% probability of extinction. Extinction risk estimates may be conservative when human activities and other related threats to species persistence are considered.
- Paleogene equatorial penguins challenge the proposed relationship between biogeography, diversity, and Cenozoic climate change
Julia A. Clarke, Daniel T. Ksepka, Marcelo Stucchi, et al.
Proceedings of the National Academy of Sciences, USA, Vol. 104, No. 28, Jul 2007, pp. 11545-11550.
New penguin fossils from the Eocene of Peru force a reevaluation of previous hypotheses regarding the causal role of climate change in penguin evolution. Repeatedly it has been proposed that penguins originated in high southern latitudes and arrived at equatorial regions relatively recently (e.g., 4-8 million years ago), well after the onset of latest Eocene/Oligocene global cooling and increases in polar ice volume. By contrast, new discoveries from the middle and late Eocene of Peru reveal that penguins invaded low latitudes >30 million years earlier than prior data suggested, during one of the warmest intervals of the Cenozoic. A diverse fauna includes two new species, here reported from two of the best exemplars of Paleogene penguins yet recovered. The most comprehensive phylogenetic analysis of Sphenisciformes to date, combining morphological and molecular data, places the new species outside the extant penguin radiation (crown clade: Spheniscidae) and supports two separate dispersals to equatorial (paleolatitude approximately 14 degree S) regions during greenhouse earth conditions. One new species, Perudyptes devriesi, is among the deepest divergences within Sphenisciformes. The second, Icadyptes salasi, is the most complete giant (>1.5 m standing height) penguin yet described. Both species provide critical information on early penguin cranial osteology, trends in penguin body size, and the evolution of the penguin flipper.
- Penguin colonies as secondary sources of contamination with persistent organic pollutants
L. Roosens, N. Van Den Brink, M. Riddle, R. Blust, H. Neels and A. Covaci.
Journal of Environmental Monitoring, Vol. 9, No. 8, Aug 2007, pp. 822-825.
Although long-range atmospheric transport has been described as the predominant mechanism for exposing polar regions to persistent organic pollutants (POPs), recent studies have suggested that bird activity can also contribute substantially to contaminant levels in some environments. However, because the species so far reported have all been migratory, it has not been demonstrated conclusively whether locally elevated contamination represents transport from lower latitudes by the migrating birds or, alternatively, redistribution and concentration of contaminants that were already present in the high-latitude environments. The present study demonstrates, for the first time, that several POPs are present in elevated concentrations in an environment frequented by a non-migratory species (Adelie penguins) that spends its entire life in the Antarctic. Levels of POPs, such as p, p'-DDE, hexachlorobenzene (HCB), chlordanes (CHLs) and polychlorinated biphenyls (PCBs), were 10 to 100-fold higher in soil samples from penguin colonies than from reference areas. This significant difference is likely related to local penguin activity, such as a higher abundance of guano and the presence of bird carcasses. This hypothesis is also supported by a higher percentage of persistent congeners (PCB 99, 118, 138 and 153) in the soil from the colonies compared to the reference areas. This profile of PCB congeners closely matched profiles seen in penguin eggs or penguin blood.
- Regulation compliance by vessels and disturbance of harbour seals (Phoca vitulina)
Amber Johnson and Alejandro Acevedo-Gutiérrez.
Canadian journal of zoology, Vol. 85, No. 2, Feb 2007, pp. 290-294.
The US National Oceanic and Atmospheric Administration established a buffer zone around marine mammals to prevent harassment. The buffer zone varies by species listing status and by geographic area. However, it is unknown the extent to which vessels comply with these buffer zones. We selected harbor seals (Phoca vitulina L., 1758) as a case study to describe compliance with the buffer zone. We conducted land-based observations from Yellow Island, Washington State, in a geographic area where the buffer zone is 91 m (100 yards), to estimate vessel distance from hauled-out seals and to evaluate seal response. We recorded 85.7% of kayaks, 57.1% of stopped powerboats, and 4.6% of passing powerboats violating the buffer zone. Seals were disturbed by kayaks and stopped powerboats at distances >91 m from the haul-out sites but not by moving powerboats ≤91 m from the sites. Hence, compliance of the buffer zone varied with vessel type and vessel activity. We suggest that a larger buffer zone for vessels lingering around the haul-out sites and enforcement of the buffer zone will minimize seal disturbance. [PUBLICATION ABSTRACT]
- Biological Effects of El Nino on the Galapagos Penguin
FHarnan Vargas, Scott Harrison, Solanda Rea and David W. Macdonald.
Biological Conservation, Vol. 127, No. 1, Jan 2006, pp. 107.
The biological effects of El Nino Southern Oscillation (ENSO) were evaluated on the population dynamics of the penguin. The biological effects of El Nino activity from 1965 to 2004 were examined using instrumental sea-surface temperatures from the Galapagos Islands and 20 years of census counts of the Galapagos penguin. Between 1965 and 2004, nine El Nino events were recorded in which two strong El Nino events namely 1982-1983 and 1997-1998 were followed by crashes of 77 percent and 65 percent of the penguin population respectively. The 2004 penguin population was estimated to be less than 50 percent of that prior to the strong 1982-1983 El Nino event.
- Contrasting Population Changes in Sympatric Penguin Species in Association with Climate Warming
Jaume Forcada, P. N. Trathan, K. Reid, E. J. Murphy and J. P. Croxall.
Global Change Biology, Vol. 12, No. 3, Mar 2006, pp. 411.
The contrasting population changes in sympatric penguin species in association with climate warming were examined. These trends occurred in parallel with regional long-term warming and significant reduction in sea ice extent. Periodical warm events, with teleconnections to the tropical pacific, caused cycles in sea ice leading to reduced prey biomass, and simultaneous interannual population decreases in the three penguin species. Chinstrap penguins, considered to be better adapted to ice-free conditions, affected by discrete events of locally increased ice over, but showed less variable, nonlinear responses to sea ice loss. Gentoo penguins were temporarily affected by negative anomalies in regional sea ice, but persistent sea ice reductions were likely to increase their available niche, which was likely to be substantially segregated from that of their more abundant congeners.
- A 50-Years Record of Dichloro-Diphenyl-Trichloroethanes and Hexachloro-Cyclohexanes in Lake Sediments and Penguin Droppings on King George Island, Maritime Antarctic
Li-guang, Yin Xue-bin, Pan Can-ping and Wang Yu-hong.
Journal of Environmental Sciences (China), Vol. 17, No. 6, 2005, pp. 899.
The temporal organochlorine pesticides (OCPs) profiles in the two lake cores over the past 50 years and their differences from King George Island, West Antarctica were presented. The research material was collected in March 2000 from Niudu Lake about 50 m from the Nelson Ice Cap, West Antarctica. All the samples were stored at -24 degree C prior to organochlorine pesticide analysis. To investigate the change of OCPs loading in Antarctic coastal ecosystem, the hexachlorocyclohexane (HCH) and dichloro-diphenyl-trichloroethane (DDT) concentration profiles were reconstructed. There was gradual increase for the former and a continuous decrease for the latter during the past 50 years. The increase in HCH seemed to be due to the regional warming from the early 1970s and the resulted HCH discharge to the coastal ecosystem by glaciers' meltwater and the illegal use of HCH in the Southern Hemisphere in the recent decade.
- Review of The Adélie Penguin: Bellwether of Climate Change
Animal Behaviour, Vol. 65, No. 6, 2003, pp. 1248-1250.
This book summarizes our current knowledge of the Adélie penguin, through an updated review of the species' life history traits, and examines the ecological factors that influence the mechanisms by which it is responding to climate change in the Antarctic marine ecosystem. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
- Silenced spring: Disappearing birds
The Futurist, Vol. 37, No. 4, Jul/Aug 2003 2003, pp. 39.
Almost 1,200 bird species-about 12% of those remaining in the world-may face extinction within the next century. Most struggle against a deadly mixture of threats, including habitat loss, human disasters, and disease. Although some bird extinctions now seem imminent, many can still be avoided with deep commitment to conservation as an integral part of a sustainable development strategy. Today, loss or damage to species' living spaces poses by far the greatest threat to birds and biodiversity in general. Even in otherwise undisturbed wildlife habitats, a new order is taking hold as exotic (nonnative) species are introduced. Other threats come from human activities, such as unregulated hunting and trapping. The wild bird pet trade has also been devastating. Global warming is another threat to birds. The actions needed to ensure a secure future for birds are the same ones needed to achieve a sustainable human future.
- Environmental Change and Antarctic Seabird Populations
J. P. Croxall, P. N. Trathan and E. J. Murphy.
Science (Washington), Vol. 297, No. 5586, Aug 30, 2002, pp. 1510.
Evidence of recent changes in populations of Antarctic seabirds may prove to be an important indicator of direct and indirect responses to on-going regional climate change. Analyses of the best available long-term data for high-latitude Antarctic seabirds (e.g., Adelie and Emperor penguines, and snow petrels) have underscored the strong influence of winter sea-ice. Inconsistencies in the data between species and areas are discussed. Researchers concluded that the combined pressures of recent harvest-driven changes and on-going anthropogenic climate warming are likely to result in abrupt changes rather than in gradual changes in these populations.
- Caught in a Melting World
Tui De Roy.
International Wildlife, Vol. 30, No. 6, Nov 2000, pp. 12.
The Adelie penguins of Antarctica live, breed, and nest on and near the massive floes of ice that move through the ocean delivering the penguins to feeding grounds rich in krill. The timing of ice melts is critical to the feeding and breeding habits of the species; these habits are thus directly affected by the impact of global warming on the melting process. In the past 25 years, the numbers of breeding pairs at five colonies have declined from 15,200 to 9,200. Smaller colonies have disappeared altogether. Food shortages in the northernmost and warmest part of the range caused by the shift in sea temperature are blamed for much of the decline. The nesting grounds are also covered with more snow, which delays breeding and chills new chicks with melting snow. Additionally, the ice algae on which krill feed is less productive because of the higher solar ultraviolet radiation transmitted through the broken ozone layer.
- Climate Fluctuation Effects on Breeding of Blue Penguins (Eudyptula minor)
Lyndon Perriman, Dave Houston, Harald Steen and Edda Johannesen.
New Zealand Journal of Zoology, Vol. 27, No. 4, Dec 2000, pp. 261.
Six years (19931998) of data from five blue penguin breeding colonies on New Zealand's Otago coast were analyzed for possible correlations between annual variation in breeding success and El Nio/La Nia climate perturbations (quantified as Southern Oscillation Index [SOI] values). During La Nia conditions, onset of breeding was later and the proportion of pairs with two clutches per year was lower than during El Nio or normal years. This result mainly reflected the very late breeding and very low proportion of double breeders during 1998, a year that followed an El Nio year. A correlation with SOI values was also found for fledging success, but not for hatching success or overall breeding success. Results suggest that the breeding success of blue penguins is not strongly influenced by large-scale climatic fluctuations.
- Humboldt penguins outmanoeuvring El Nino
B. Culik, J. Hennicke and T. Martin.
Journal of Experimental Biology, Vol. 203, No. 15, 2000, pp. 2311-2322.
We satellite-tracked five Humboldt penguins during the strong 1997/98 El Nino Southern Oscillation (ENSO) from their breeding island Pan de Azucar (26 degree 09'S, 70 degree 40'W) in northern Chile and related their activities at sea to satellite-derived information on sea surface temperature (SST), sea surface temperature anomaly (SSTA), wind direction and speed, chlorophyll a concentrations and statistical data on fishery landings. We found that Humboldt penguins migrated by up to 895 km as marine productivity decreased. The total daily dive duration was highly correlated with SSTA, ranging from 3.1 to 12.5 h when the water was at its warmest (+4 degree C). Birds travelled between 2 and 116 km every day, travelling further when SSTA was highest. Diving depths (maximum 54 m), however, were not increased with respect to previous years. Two penguins migrated south and, independently of each other, located an area of high chlorophyll a concentration 150 km off the coast. Humboldt penguins seem to use day length, temperature gradients, wind direction and olfaction to adapt to changing environmental conditions and to find suitable feeding grounds. This makes Humboldt penguins biological in situ detectors of highly productive marine areas, with a potential use in the verification of trends detected by remote sensors on board satellites.
- Investigations into Climate Influence on Population Dynamics of Yellow-Eyed Penguins Megadyptes antipodes
L. Peacock, M. Paulin and J. Darby.
New Zealand Journal of Zoology, Vol. 27, No. 4, Dec 2000, pp. 317.
Using long-term (19811993) population monitoring data for yellow-eyed penguins on the Otago Peninsula, New Zealand, an exploratory analysis was done to determine whether population fluctuations of this regionally rare and threatened species were correlated with climate fluctuations. Population variables were strongly correlated with rainfall and sea surface temperature. Computer modeling indicated that this relationship was not due to chance and that fledgling success increased in cool/wet seasons. Conversely, a model using historical data (19361949) showed that the penguin population increased in warm/dry seasons. Possible reasons for this reversed pattern are discussed, including the recent climate change toward higher temperatures and more variable rainfall levels. Results suggest that the gradual decline in yellow-eyed penguin numbers may be related to long-term climate change in general rather than to El Nio-Southern Oscillation events in particular.
- Incidental mortality of Humboldt Penguins Spheniscus humboldti in gill nets, central Chile
A. Simeone, M. Bernal and J. Meza.
Marine Ornithology, Vol. 27, Mar 1999, pp. 157-161.
Mortality of Humboldt Penguins Spheniscus humboldti drowned in gill nets is documented for the Valparaiso Region, central Chile, based on sampling and reports from local fishermen. Between 1991 and 1996 at least 605 Humboldt Penguins died in gill nets set for `corvina' Cilus gilberti, an average of 120 birds per year. Lesser numbers of other seabirds, including Magellanic Penguins S. magellanicus, Red-legged Cormorants Phalacrocorax gaimardi and Guanay Cormorants P. bougainvillii were killed. Drownings occur mainly during winter (June to August), reducing the population prior to the spring breeding season. Drowning kills adults from the two major colonies of Humboldt Penguins in central Chile, Cachagua and Pajaro Nino. Entanglement of Humboldt Penguins in fishing nets has been reported for other sites in Chile and Peru, suggesting similar mortality along most of the species' range.
- Marine Ecosystem Sensitivity to Climate Change
R. C. Smith, D. Ainley, K. Baker, et al.
Bioscience, Vol. 49, No. 5, May 1999, pp. 393.
Historical observations and paleoecological records reveal ecological transitions in the Antarctic Peninsula region. This century's rapid climate warming is occurring concurrently with a shift in the population size and distribution of penguin species.
- Abandoned Penguin Colonies and Environmental Change in the Palmer Station Region, Anvers Island, Antarctic Peninsula
Steven D. Emslie, William Fraser, Raymond C. Smith and William Walker.
Antarctic Science, Vol. 10, No. 3, Sep 1998, pp. 257.
Relationships between Adelie penguin colony nesting and environmental change were studied by excavating six abandoned nesting sites near Palmer Station, Anvers Island, Antarctica. Analysis of prey and food remains and radiocarbon analysis showed that Adelie penguins may have changed their diet in response to warming and cooling cycles in the past. While only Adelie penguins are known to have nested at this site before the 1950s, gentoo and chinstrap penguins now breeding there have expanded their range southward in the Antarctic Peninsula over the last 50 yr, in correlation with marked warming of the region.
- Cold Comfort
Thomas Hayden and Sharon Begley.
Newsweek, Vol. 130, No. 6, Aug 11, 1997, pp. 62.
Emperor penguins native to Antarctica must adapt to the gradual warming of their climate. This makes them more vulnerable to breeding failures. Scientists are uncertain whether the warming is caused by natural climate fluctuations or global warming. Nevertheless, a warmer atmosphere increases the moisture level, as indicated by higher snowfalls. This in turn affects penguin populations. The Adelie penguin breeding pair population has dropped from 15,200 in 1975 to 9,200 in 1997. Six of the breeding colonies are now extinct. Reduced levels of sea ice have compromised krill populations, an important link in the food chain, and the algae upon which they feed. Fledgling survival has been greatly reduced since the 1970s.
- Is Warming Trend Harming Penguins?
Science-AAAS, Vol. 276, No. 5320, Jun 20, 1997, pp. 1790.
Over the past 50 years, scientists have observed a 4-5 degree C midwinter warming of the western Antarctic Peninsular climate. The impacts of this warming on populations of the Adelie penguin are analyzed. Some ecologists believe that declining sea ice cover due to warming may be one of the main causes of recent declines in penguin numbers. Recent research also suggests that the warming may be causing greater levels of snowfall in the region. This increased snowfall may restrict the ability of the birds to breed successfully. In 1975, the Adelie penguin populations on five islands near Palmerston Station numbered a total of 15,200 breeding pairs. At present, only 9200 breeding pairs survive on these islands. Other potential causes of these population declines are discussed.
- Heavy metals in some parts of Antarctica and the Southern Indian Ocean
T. Kureishy, R. Sen Gupta, A. Mesquita and S. Sanzgiry.
Marine pollution bulletin, Vol. 26, No. 11, Mar 1993, pp. 651-652.
Though remote in its geographical location Antarctica is known to be indirectly affected by industrial and agricultural activities on other continents. This is evident in the concentrations of synthetic chemicals such as the organochlorine pesticides which are present in the Antarctic environment. There is a need to investigate heavy metal levels in the Antarctic continent, as these contaminants may also be subject to aerial transport. Baseline studies suggest that metals may be of significance as marine pollutants in some part of the Antarctic continent. During the 7th Indian scientific expedition to Antarctica, the concentrations of certain trace metals were determined in various samples. Zooplankton and krill were collected from 30 degree S to the Southern ocean. Lichens and moss were collected from the shores of glacial lakes around the Indian station Maitri in the Schirmacher Oasis. Sediments from three different lakes were also collected. Penguin feathers, providing a measure of metal accumulation over two years, were also sampled.
- Winter breeding in emperor penguins: a consequence of the summer heat?
B. Pinshow and W. R. Welch.
Condor, Vol. 82, No. 2, 1980, pp. 159-163.
During their Antarctic breeding season emperor penguins (Aptenodytes forsteri ) fast as long as 115 days and walk as far as 200 km from the sea to their rookeries and back. The breeding males stand on the ice incubating a single egg for about 62 days. The thermal exchanges between emperor penguins and their environment were examined in an attempt to answer the question: Why do these penguins breed during the winter? Existing physiological data for the temperature regulation of emperor penguins were used in conjunction with meterological data frm the Antarctic to model thermal interactions between the animal and its environment. Computer simulations for the energy budget of emperor penguins in a variety of microclimatic conditions indicate that the heat load imposed on these birds during the Antarctic summer does not limit their choice of breeding season. It is concluded that the physiological and morphological characteristics associated with heat exchange do not constrain emperor penguins to winter breeding.