Like many polar animals, emperor penguin populations are challenging to monitor because of the species’ life history and remoteness. Consequently, it has been difficult to establish its global status, a subject important to resolve as polar environments change. To advance our understanding of emperor penguins, we combined remote sensing, validation surveys, and using Bayesian modeling we estimated a comprehensive population trajectory over a recent 10-year period, encompassing the entirety of the species’ range. Reported as indices of abundance, our study indicates with 81% probability that the global population of adult emperor penguins declined between 2009 and 2018, with a posterior median decrease of 9.6% (95% credible interval (CI) -26.4% to +9.4%). The global population trend was -1.3% per year over this period (95% CI = -3.3% to +1.0%) and declines likely occurred in four of eight fast ice regions, irrespective of habitat conditions. Thus far, explanations have yet to be identifi..., During the 2018 Antarctic field season, under permit #2019-006 granted by the National Science Foundation, our US-based team conducted aerial photography at emperor penguin colonies in the Ross Sea to add to robust validation of imagery. Our efforts included one flight via fixed wing aircraft over colonies distant from McMurdo Station and five flights via helicopter to a single colony (Cape Crozier) near the station. The five flights to Cape Crozier, 24 October to 15 November, were used to better understand population fluctuation through a single season. Our fixed wing survey took place on 31 October 2018, flying in the vicinity of Beaufort Island (ASPA 105), Franklin Island, Cape Washington (ASPA 173), Coulman Island, and Cape Roget. At each location (both by fixed wing and helicopter), we circled the colony 1-4 times, maintaining a minimum of 500 m horizontal distance from the periphery of the colony and a minimum altitude of 500 m. No behavioral disturbance to birds (e.g., rapid move..., , # LaRue et al. (2024): Advances in remote sensing of emperor penguins: first multi-year time series documenting global population change

10.5061/dryad.m63xsj48v

Overview

This repository contains data, code, and model output associated with the global-scale analysis of Emperor penguin population dynamics described in LaRue et al. (2024), based on integrating raw data from aerial surveys with time series of circumpolar satellite surveys of known emperor penguin colonies.

The model is used to estimate an annual index of abundance at every known Emperor penguin colony in Antarctica (as of 2018), for every year between 2008 and 2018. Regional and global population indices are then calculated by summing colony-level estimates, according to regional colony membership.

Simulations are also performed to evaluate the ability of the model to accurately detect population trends, if they exist.

File structure and code description

• analysis/
  • **ou...

Data were collected from two penguin monitoring sites in the Antarctic peninsula region between 1977 and 2015 using traditional census methods. Seabirds observed in this study are Adélie (Pygoscelis adeliae), chinstrap (P. antarctica), and gentoo (P. papua) penguins. The two study sites are the US AMLR Program sites at Cape Shirreff (Livingston Island) and Copacabana (King George Island).

The fundamental long-term objective of the seabird component of the Palmer LTER (PAL) has been to identify and understand the mechanistic processes that regulate the mean fitness (population growth rate) of regional penguin populations. Since the inception of PAL, Adélie penguin populations have effectively collapsed, gentoo penguin populations have increased dramatically and chinstrap penguin populations have remained relatively stable. These trends are spatially and temporally coherent with regional warming and decreasing sea ice duration. Adélie penguins are an ice-obligate polar species whose life history is intimately linked to the presence of sea ice, while chinstrap and gentoo penguins are ice-intolerant species whose life histories evolved in the sub-Antarctic, where sea ice is a less permanent feature of the marine ecosystem. The PAL study region includes five main islands on which Adélie penguin colonies have historically occurred, with each island containing a different number of spatially segregated sub-colonies. These colonies are censused to determine the total number of nests and chicks produced each year, and breeding success. Diet samples are acquired to understand diet composition (e.g., krill, fish) and krill length-frequencies. In general, krill constitute the most important component of the summer diets by mass of these three penguin species, but changes in PAL krill abundances have exhibited no long-term trends and thus far, have failed to explain the divergent patterns in penguin populations evident in our time series. Chick fledging masses are recorded as a cumulative measure of climate, weather, diet, and parental influences on chick health at the end of the breeding season. These data have provided valuable insights into the marine and terrestrial factors that influence Adélie penguin population fitness. No data were collected during the 2021-2022 season due to the Palmer Station pier rebuild.

This indicator is no longer maintained, and is considered OBSOLETE. INDICATOR DEFINITION Demographic parameters for the Adelie penguin at Bechervaise Island near Mawson. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION The Adelie penguin is a relatively long lived sea bird dependent on krill. It is expected that major changes in the availability of food (krill) to sea birds will be reflected ultimately in recruitment into the breeding population. Causes of changes in the availability of krill relate directly to changes in both the biological and physical environment brought about by man made or natural means. Ageing populations may give an outward appearance of stability in terms of numbers at a breeding colony but such a condition may mask a decline in recruitment. To determine whether there are environmental influences on the population it is necessary to undertake detailed demographic studies. Demographic studies carried out over many years on animal populations comprising known age cohorts are required to determine those factors responsible for any observed changes in recruitment and/or mortality. Population reconstruction techniques provide estimates of recruitment and mortality and relate these functions to population size and/or population trends. These studies may alert us to possible changes in the ecosystem particularly related to the availability of food to the penguins or changes to the physical environment. The identification of the cause of changes must come from detailed investigations of food availability and the environment carried out at the same time. Annual breeding success at Bechervaise Island (eggs laid to chicks fledged) varies enormously from 0 in catastrophic years to above 1 for good seasons. The population at Bechervaise Island near Mawson has been monitored since 1990 as part of the CCAMLR Ecosystem Monitoring Program. Chicks and adults have been tagged annually. The number of breeding pairs has increased slightly between 1990-2001, but changes in the non -breeding population are unknown. Demographic studies based on the return rate of birds tagged as chicks provide information on trends in the overall population and the net rate of recruitment. Since it is intended that this program be undertaken indefinitely it makes this population an excellent subject for monitoring in the context of the SOE. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial Scale: Restricted to the Mawson region. Similar studies are carried out by other national research programs at Terra Nova Bay (Italy) and on the Antarctic Peninsula (USA). Frequency: Annual Measurement Technique: The Adelie penguin population at Bechervaise Island consists of approximately 1800 breeding pairs. Each breeding season since 1990/91 in excess of 250 chicks have been given implanted electronic identification tags. The return of birds to their natal colony has been detected automatically by the Automated Penguin Monitoring System (APMS)or by checking all birds with a hand held tag reader. Additional and associated biological data as prescribed by CCAMLR (1997 are collected to aid interpretation of demographic and other trends. To detect trends in the population size and in demographic parameters, particularly of recruitment, it will be necessary to maintain an annual tagging program of chicks and recording of all tagged birds. RESEARCH ISSUES comprehensive analysis of the data collected over the duration of this study is required to determine natural variation and potential anthropogenic influences affecting Adelie penguin population dynamics. LINKS TO OTHER INDICATORS Sea-ice extent and concentration.

The fundamental long-term objective of the seabird component of the Palmer LTER (PAL) has been to identify and understand the mechanistic processes that regulate the mean fitness (population growth rate) of regional penguin populations. Since the inception of PAL, Adélie penguin populations have effectively collapsed, gentoo penguin populations have increased dramatically and chinstrap penguin populations have remained relatively stable. These trends are spatially and temporally coherent with regional warming and decreasing sea ice duration. Adélie penguins are an ice-obligate polar species whose life history is intimately linked to the presence of sea ice, while chinstrap and gentoo penguins are ice-intolerant species whose life histories evolved in the sub-Antarctic, where sea ice is a less permanent feature of the marine ecosystem. The PAL study region includes five main islands on which Adélie penguin colonies have historically occurred, with each island containing a different number of spatially segregated sub-colonies. These colonies are censused to determine the total number of nests and chicks produced each year, and breeding success. Diet samples are acquired to understand diet composition (e.g., krill, fish) and krill length-frequencies. In general, krill constitute the most important component of the summer diets by mass of these three penguin species, but changes in PAL krill abundances have exhibited no long-term trends and thus far, have failed to explain the divergent patterns in penguin populations evident in our time series. Chick fledging masses are recorded as a cumulative measure of climate, weather, diet, and parental influences on chick health at the end of the breeding season. These data have provided valuable insights into the marine and terrestrial factors that influence Adélie penguin population fitness. No data were collected during the 2021-2022 season due to the Palmer Station pier rebuild.

We hypothesized that regional spatial organization of Antarctic penguin breeding populations was affected by social factors, i.e., proximity and size of adjacent colonies, and by physical factors, i.e., availability of breeding habitat and proximity of polynyas and submarine canyons where prey is abundant. The hypothesis of Furness & Birkhead (1984), that forage competition and density-dependence affect geographic structure of seabird populations, was tested previously for Antarctic penguins when biologging to quantify colony foraging areas was less common and when assessments of colony size reflected a compendium of historical counts. These data on foraging areas and colony size are now available following 20 years of frequent biologging and real-time satellite data on colony locations and sizes. We prepared a literature summary on the basis of biologging studies to improve assessment of foraging ranges. We collated colony sizes from recent sources and integrated them with data on submarine canyon systems and polynyas. We used geospatial models to assess the relations of the latter features to colony size, clustering, and distribution around Antarctica. The equal spacing of emperor penguin colonies was constant, with spacing a function of foraging range. In contrast, colonies of other penguin species were clustered, with small colonies adjacent to one another and within outer edge of the foraging area of large colonies. Colonies and especially clusters occurred near polynyas and canyons around Antarctica. Density-dependent processes and geography explained penguin colony distribution. We conclude that inter- and intraspecific trophic competition affects a geographic structuring of colony distribution and size, although not necessarily in the same way among species. Results are relevant to assessing effects of climate and other factors on penguin population trends at regional scales. We suggest that considering penguin colony distribution and abundance at the regional or cluster level is necessary to understand changes in these attributes See Methods and Supplemental Materials for description of data summary and processing. A ReadMe file is included in the data package describing the various data layers.

Ground counts of King Penguin Aptenodytes patagonicuseggs, chicks, fledglings and adults at Gadget Gully on Macquarie Island (1993-2008 incomplete). Counts were obtained in the field by observers at Gadget gully. During the late 19th and early 20th centuries, when blubber oil fuelled house lamps, the king penguin population at Macquarie Island was reduced from two very large (perhaps hundreds of thousands of birds) colonies to about 3000 birds. One colony, located on the isthmus when the island was discovered in 1810, was extinct by 1894 and it took about 100 years for king penguins to re-establish a viable breeding population there. Here we document this recovery. The first eggs laid at Gadget Gully on the isthmus were recorded in late February 1995 but in subsequent years egg laying took place earlier between November and February (this temporal discontinuity is a consequence of king penguin breeding behaviour). The first chick was hatched in April 1995 but the first fledging was not raised until the following breeding season in October 1996. The colony increased on average 66% per annum in the five years between 1995 and 2000. King penguins appear resilient to catastrophic population reductions, and as the island’s population increases, it is likely that other previously abandoned breeding sites will be reoccupied.

Seabirds are considered to be useful and practical indicators of the state of marine ecosystems because they integrate across changes in the lower trophic levels and the physical environment. Signals from this key group of species can indicate broad scale impacts or response to environmental change. Recent studies of penguin populations, the most commonly abundant Antarctic seabirds in the west Antarctic Peninsula and western Ross Sea, have demonstrated that physical changes in Antarctic marine environments have profound effects on biota at high trophic levels. Large populations of the circumpolar-breeding Adélie penguin occur in East Antarctica, but direct, standardized population data across much of this vast coastline have been more limited than in other Antarctic regions. We combine extensive new population survey data, new population estimation methods, and re-interpreted historical survey data to assess decadal-scale change in East Antarctic Adélie penguin breeding populations. We show that, in contrast to the west Antarctic Peninsula and western Ross Sea where breeding populations have decreased or shown variable trends over the last 30 years, East Antarctic regional populations have almost doubled in abundance since the 1980’s and have been increasing since the earliest counts in the 1960’s. The population changes are associated with five-year lagged changes in the physical environment, suggesting that the changing environment impacts primarily on the pre-breeding age classes. East Antarctic marine ecosystems have been subject to a number of changes over the last 50 years which may have influenced Adélie penguin population growth, including decadal-scale climate variation, an inferred mid-20th century sea-ice contraction, and early-to-mid 20th century exploitation of fish and whale populations.

Understanding the boundaries of breeding populations is of great importance for conservation efforts and estimates of extinction risk for threatened species. However, determining these boundaries can be difficult when population structure is subtle. Emperor penguins are highly reliant on sea ice, and some populations may be in jeopardy as climate change alters sea-ice extent and quality. An understanding of emperor penguin population structure is therefore urgently needed. Two previous studies have differed in their conclusions, particularly whether the Ross Sea, a major stronghold for the species, is isolated or not. We assessed emperor penguin population structure using 4,596 genome-wide single nucleotide polymorphisms (SNPs), characterized in 110 individuals (10–16 per colony) from eight colonies around Antarctica. In contrast to a previous conclusion that emperor penguins are panmictic around the entire continent, we find that emperor penguins comprise at least four metapopulations,...

This dataset contains model input and output data on emperor penguin population dynamics for a Bayesian analysis carried out on multivariate classification results. Model input data comprises multivariate classification analysis results derived from very-high resolution (VHR) satellite imagery pertaining to 16 emperor penguin colonies, spanning the Bellingshausen Sea to the Weddell Sea between 2009 to 2023. Model output data comprises population estimates for each year for each colony, global trends per year, global change for the dataset overall, global abundance pertaining to individual colonies, as well as statistical parameter estimates provided by the model.

Data collection was carried out by personnel at BAS.

Funding from WWF UK (GB095701), project NE/Y00115X/1 "Understanding emperor penguin populations in the Weddell Sea and Antarctic Peninsula" and previous WWF funding over the 15 year period.

The fundamental long-term objective of the seabird component of the Palmer LTER (PAL) has been to identify and understand the mechanistic processes that regulate the mean fitness (population growth rate) of regional penguin populations. Two hypotheses have guided this research, with one suggesting that population mean fitness is best explained by changes in regional krill biomass, and the other proposing that long-term changes in sea ice affects mean fitness by tipping the balance in favor of one species over another in accordance with species-specific evolved life history affinities to sea ice. Although these hypotheses are not mutually exclusive, current evidence in the PAL region tends to favor the latter over the former. Since the inception of PAL, Adélie penguin populations have effectively collapsed, while those of gentoo and chinstrap penguins have increased dramatically, trends that are spatially and temporally coherent with decreasing regional sea ice duration. Adélie penguins are an ice-obligate polar species whose life history is intimately linked to the presence of sea ice, while chinstrap and gentoo penguins are ice-intolerant species whose life histories evolved in the sub-Antarctic, where sea ice is a less permanent feature of the marine ecosystem. In contrast, although krill constitute the most important component of the summer diets by mass of these three penguin species, changes in PAL krill abundances have exhibited no long-term trends, and thus fail to explain the divergent patterns in penguin populations evident in our time series. The PAL study region includes five main islands on which Adélie penguin colonies have historically occurred. These are censused synoptically once a year to determine the overall size of the breeding population. The optimal census date may vary by a few days each season, but ultimately tries to capture the week following peak egg laying when the total number of breeding pairs reaches a maximum. The timing of this census is assisted by the REPRO and HUMPOP data, which provide a daily to weekly rate of change in breeding adult population numbers as new nests are initiated. This census is useful for a number of assessments, one of the most critical being that it directly reflects the effects of environmental variability on adult overwinter survival. Dr. Megan Cimino took over as PI of the LTER seabird project in 2020 from Dr. William Fraser. Field data collection between 2020-2022 has remained consistent with previous years.

Metadata record for data from ASAC Project 484 See the link below for public details on this project. ---- Public Summary from Project ---- Emperor penguins are the only birds that breed in the Antarctic winter. They feed mainly on fish and squid but also ingest krill. Changes in food availability due to oceanographic or climatic factors, or to the extent of sea ice (through the processes of global warming) will have a direct impact on the breeding success and population size of the penguins. By counting the number of males that incubate at mid-winter each year, we can monitor trends in their population size. Counts of fledglings in spring (November) tell us how successful the penguins bred. The download file contains an excel spreadsheet which presents a summary of known Emperor Penguin colonies in the area of the Australian Antarctic Territory (AAT), and a file which details counts of male emperor penguins at the Taylor Glacier colony. A description of the column headings used in the spreadsheet is below. Colony: Colony name lat, long: latitude and longitude of colony discovered: date colony was discovered current est pop (BP): Current estimated population size in breeding pairs - current as at date the colony was last seen last seen: date the colony was last seen counting method: method used to count the breeding pairs in the colony comments: any applicable comments reference: references relating to the colony Taken from the 2009-2010 Progress Report: Public summary of the season progress: Population size of colonies fluctuates which is why long term monitoring studies are necessary to detect trends. At the emperor penguin colony at Taylor Glacier, monitored continuously since 1988, a slight downward trend is apparent but is not (yet?) statistically significant. The colony was visited three times: once in winter to obtain an estimate of the number of adults in the colony (roughly equivalent to the number of breeding pairs), and twice during the late chick rearing season to estimate breeding success. The count of adults in 2009 was the lowest on record. Reasons for this are still unknown.

The fundamental long-term objective of the seabird component of the Palmer LTER (PAL) has been to identify and understand the mechanistic processes that regulate the mean fitness (population growth rate) of regional penguin populations. Two hypotheses have guided this research, with one suggesting that population mean fitness is best explained by changes in regional krill biomass, and the other proposing that long-term changes in sea ice affects mean fitness by tipping the balance in favor of one species over another in accordance with species-specific evolved life history affinities to sea ice. Although these hypotheses are not mutually exclusive, current evidence in the PAL region tends to favor the latter over the former. Since the inception of PAL, Adélie penguin populations have effectively collapsed, while those of gentoo and chinstrap penguins have increased dramatically, trends that are spatially and temporally coherent with decreasing regional sea ice duration. Adélie penguins are an ice-obligate polar species whose life history is intimately linked to the presence of sea ice, while chinstrap and gentoo penguins are ice-intolerant species whose life histories evolved in the sub-Antarctic, where sea ice is a less permanent feature of the marine ecosystem. In contrast, although krill constitute the most important component of the summer diets by mass of these three penguin species, changes in PAL krill abundances have exhibited no long-term trends, and thus fail to explain the divergent patterns in penguin populations evident in our time series. The PAL study region includes five main islands on which Adélie penguin colonies have historically occurred. These are censused synoptically once a year to determine the total number of chicks produced in the area. The optimal date for this census may vary by a few days each season, but ultimately tries to capture the week following the time when approximately 2/3 of the chicks have crèched. The timing of this census is assisted by the REPRO data, which provide a daily to weekly rate of change in the number of crèched chicks. Because the colonies used in this area-wide census are the same as those used to determine the overall annual breeding population, one of the key metrics obtained is an integrated number of breeding success (chicks crèched/breeding pair). These data have provided valuable insights into the marine and terrestrial factors that influence Adélie penguin mean population fitness. Dr. Megan Cimino took over as PI of the LTER seabird project in 2020 from Dr. William Fraser. Field data collection between 2020-2022 has remained consistent with previous years. No data collected during the 2021-2022 season due to the Palmer Station Pier Build.

The Adélie penguin is the most important animal currently used for ecosystem monitoring in the Southern Ocean. The diet of this species is generally studied by visual analysis of stomach contents; or ratios of isotopes of carbon and nitrogen incorporated into the penguin from its food. There are significant limitations to the information that can be gained from these methods. We evaluated population diet assessment by analysis of food DNA in scats as an alternative method for ecosystem monitoring with Adélie penguins as an indicator species. Scats were collected at four locations, three phases of the breeding cycle, and in four different years. A novel molecular diet assay and bioinformatics pipeline based on nuclear small subunit ribosomal RNA gene (SSU rDNA) sequencing was used to identify prey DNA in 389 scats. Analysis of the twelve population sample sets identified spatial and temporal dietary change in Adélie penguin population diet. Prey diversity was found to be greater than previously thought. Krill, fish, copepods and amphipods were the most important food groups, in general agreement with other Adélie penguin dietary studies based on hard part or stable isotope analysis. However, our DNA analysis estimated that a substantial portion of the diet was gelatinous groups such as jellyfish and comb jellies. A range of other prey not previously identified in the diet of this species were also discovered. The diverse prey identified by this DNA-based scat analysis confirms that the generalist feeding of Adélie penguins makes them a useful indicator species for prey community composition in the coastal zone of the Southern Ocean. Scat collection is a simple and non-invasive field sampling method that allows DNA-based estimation of prey community differences at many temporal and spatial scales and provides significant advantages over alternative diet analysis approaches.

Intermittent Adelie penguin population counts for Bechervaise, Verner and Petersen Islands, Mawson since 1971. Data include counts of occupied nests for the post 1990/91 data conducted on or about 2nd December. Data collected prior to this were obtained from ANARE Research Notes or field note books. These counts may not have been performed at the 'optimal' time for occupied nests counts, and when this is the case have been adjusted according to a 'correction' factor.

The post 1990/91 data were completed as part of ASAC Project 2205, Adelie penguin research and monitoring in support of the CCAMLR Ecosystem Monitoring Project.

The fields in this dataset are:

Year Bechervaise Island Counts Verner Island Counts Petersen Island Counts Date Season occ nests (occupied nests)

Individuals and pairs of Adelie and Emperor penguins were counted at the breeding colonies near Syowa Station. Their numbers are recorded in this data set.

This dataset contains data on the habitats, distribution and numbers of Adelie Penguins (Pygoscellis adeliae) along the Vestfold Hills coast (including colonies on the mainland and offshore islands) during November 1973. The data are obtained from counts at the colonies and black and white photographs. Some aerial photographs were taken at Davis in 1981-82 and 1987-88, and will be compared to the results of this survey. The results are listed in the documentation. A total of 174178 26127 breeding pairs were counted. An increase in Adelie penguin population was found at most locations in East Antarctica.

Data from this record has been incorporated into a larger Adelie penguin dataset described by the metadata record - Annual population counts at selected Adelie Penguin colonies within the AAT (SOE_seabird_candidate_sp_AP). It also falls under ASAC project 1219 (ASAC_1219).

Table 1 presents the locations and best population estimate (BE) for each emperor penguin colony in the survey. The table also gives the image quality and the most recently published count for the colonies that have been previously counted with corresponding references.

Pairs of Adélie, chinstrap and gentoo penguins counted at Signy Island and offshore islands, 1947/48–2015/16.