Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The global population is estimated at 774,000 mature individuals (Lynch 2013).
Overall, the global population is assumed to be stable.
On the Falkland Islands (Malvinas), annual monitoring has provided increasing evidence of large fluctuations at the population scale over extended time periods (c 10-12 years; A. Stanworth pers. comm.). Reports of population declines by c.45% from 1932-33 to 1995-96 (Bingham 1998), following periods of apparent stability (Trathan et al. 1996, Bingham 2002, Clausen & Huin 2003, Crawford et al. 2009, Forcada & Trathan 2009), are within the scale of these fluctuations (A. Stanworth pers. comm.). Population trends were positive over ~15 years until recently, but populations took a downturn with a 35% drop in the number of breeding pairs between 2015 and 2016 at annually monitored sites, with a small recovery since (Crofts & Stanworth 2019). Prior to the decline in 2015, the number of breeding pairs was higher than that observed in 1932-33 (132,000 compared to 116,000) (Baylis et al. 2013). In the south-western Atlantic Ocean, rates of change simulated from census data from 70 breeding sites showed average rates of increase of 2.4% per year (Lynch et al. 2012).
In the Antarctic Peninsula, populations are increasing (Lynch et al. 2008, Ducklow et al. 2013, Lynch 2013) in tandem with a southward range expansion (Lynch 2013, Crawford et al. 2015). Here, regional populations have grown by more than 1,100% since 1974, e.g. in the Palmer Archipelago (Fountain et al. 2016, Fraser 2016).
The populations at sub-Antarctic islands may have decreased substantially in the past—at Bird Island, South Georgia by c.67% in 25 years (J. P. Croxall in litt. 1999), and at Marion Island (Prince Edward Islands) by 52% (Dyer and Crawford 2015) between 1994 and 2012. However, populations at some locations now appear to be stable or increasing (Forcada and Trathan 2009, Lynch 2013, Dunn et al. 2016), though populations are still declining at Marion Island (Crawford et al. 2014) and may still be declining on Heard Island, on Kerguelen Island (Lescroël and Bost 2006) and Crozet (C.A. Bost in litt. 2019), all in the southwest Indian Ocean. The reasons for the changes are unknown, but could be related to changing marine foodwebs.
Gentoo Penguins are defined morphologically as a single species with a northern and southern subspecies. A recent phylogenetic tree based on mitochondrial DNA showed a deep division between populations in the Indian and Atlantic oceans, with at least three distinct clades, two in the respective sub-Antarctic and Antarctic zones of the Atlantic Ocean, and a deeply divergent and unnamed third clade in the sub-Antarctic Indian Ocean (de Dinechin et al. 2012). Further phylogenetic analyses have also shown that the species shows a deep divergence between populations (Vianna et al. 2017), suggesting investigation into the taxonomic status is needed.
Pygoscelis papua has a circumpolar breeding distribution that ranges in latitude from the Fish Islands on the Antarctic Peninsula (66°01'S) (Fraser unpublished) to the Crozet Islands (46°00'S) (Lynch 2013).
Population trends are difficult to establish because of large year-to-year fluctuations in the size of the breeding population. The global population was estimated at 387,000 pairs, suggesting that the population may now be increasing, particularly in the south of its range (Lynch 2013). The three most important locations, containing 80% of the global population, are the Falkland Islands (Malvinas): 132,000 breeding pairs at about 84 breeding sites (Baylis et al. 2013), South Georgia: 98,867 pairs (South Georgia & the South Sandwich Islands) (Trathan et al. 1996) and the Antarctic Peninsula (incl. South Shetland Island): 94,751 pairs (Lynch et al. unpublished). Other breeding sites include Kerguelen Island: 30,000-40,000 pairs (Weimerskirch et al. 1988) and Crozet Island: 9,000 pairs (Jouventin 1994) in the French Southern Territories, Heard Island (to Australia): 16,574 pairs (Woehler 1993), South Orkney Islands: 10,760 pairs (Lynch et al. unpublished), Macquarie Island (Australia): 3,800 pairs, South Sandwich Islands: 1,572 pairs (Convey et al. 1999) and Prince Edward Island (South Africa): 1,000 to 1,250 pairs (Dyer and Crawford 2015). Small numbers (<100) are also found on Martillo Island and Islas de los Estados in Argentina (Bingham 1998, Ghys et al. 2008).
The species nests on flat beaches or among tussock grasses in South Georgia and the Falkland Islands, often on gentle slopes at Crozet and in grasses at Marion Island. Further south, on the Antarctic Peninsula, nests are typically on low lying gravel beaches, some rocky areas, and dry moraines. Colonies are much smaller than those of other Pygoscelis species, with the largest including only c.6,000 breeding pairs (Bost & Jouventin 1990, Lynch et al. 2008). It feeds opportunistically and preys predominantly on crustaceans, fish and squid. It preferably forages inshore, close to the breeding colony (Lescroël & Bost 2005). Winter habitats are less well studied, but available data suggest that it prefers coastal areas, while movements are more local relative to its congeners (Tanton et al. 2004, Hinke et al. 2017).
Interactions with fisheries may pose a threat to the species through incidental capture in fishing nets and resource competition (Ellis et al. 1998). The species appears to be actively feeding on discards from trawling fleets, making it susceptible to bycatch, which potentially could be causing slow but significant declines for the minority of the population whose foraging range overlaps with fisheries (Crawford et al. 2017). Future intensification of resource competition could lead to more rapid declines for exposed populations. Increasing oil exploration around the Falkland Islands is a growing concern for the species (Lynch 2013) and pollution from oil spills represents a threat on local scales.
Harmful algal blooms were attributed as the cause of the paralytic shellfish poisoning incident that resulted in a major Gentoo Penguin mortality event in 2002, from which the population took several years to recover (Pistorius et al. 2010). Hence, algal blooms appear to have the potential to cause population fluctuations in parts of the global population. Recent diseases leading to massive mortality at some colonies have also been observed recently at Crozet and Kerguelen, sometime in remote colonies (C.A Bost in litt. 2019). The origin of such diseases is still under study.
Disturbance from tourism has been shown to cause decreased breeding productivity (Trathan et al. 2008, Lynch et al. 2009, Dunn et al. 2019) and the associated marine traffic is likely to impact penguins foraging in inshore waters (Lynch et al. 2010); increased understanding about the potential impacts of tourism will therefore be important. However, sites visited by tourists collectively account for less than 5% of total population in the Falklands (Malvinas), South Georgia and British Antarctic Territories (J. Croxall in litt. 2017).
Historically, egg collection was widespread on the Falkland Islands (Malvinas) (Clausen and Pütz 2002), and some legal egg collection still continues (Otley et al. 2004).
Ingestion of plastic particles (Bessa et al. 2019) highlight the need for further assessment of the levels of microplastics in this and other penguin species in the Southern Ocean; specifically studies on temporal trends and potential effects on penguins and other organisms in the Antarctic marine food web are needed.
Gentoo Penguins and the Crozet subspecies of Imperial Shag Phalacrocorax atriceps melanogenis have considerable overlap in their diets, and their congruent declines on Marion Island were likely driven by food availability linked to benthic production around the island. Hence, the species is considered to be vulnerable to environmental changes influencing local oceanography, such as frontal positions that effect food availability at the Prince Edward Islands and elsewhere (Crawford et al. 2014). Protection of habitat on land and at sea remains important, with the designation of appropriate protection for transit, foraging and rafting areas at sea.
Conservation Actions Underway
Long-term monitoring programmes are in place at several breeding colonies. The origin of diseases at certain colonies (Crozet and Kerguelen) is under study.
Conservation Actions Proposed
Continue/extend long-term monitoring of breeding colonies. Minimize disturbance to breeding colonies. The species is very much sensitive to disturbance at the Prince Edward Islands. Consider studies of approach distance, including at colonies habituated to visitors and those with no history of visitation. Minimize oil and other pollution in breeding and foraging areas as this could have significant consequences for a sedentary inshore forager like the gentoo. Terrestrial protections for Gentoo Penguins should include the protection of breeding habitat and the minimization of colony disturbance during the breeding season. In the Antarctic, visitor site guidelines already specify minimum approach distances of 5 meters and off-limit areas.
Understanding and mitigating disease incidence or transfer, including in relation to climate anomalies such as El Niño, should be pursued. Investigate the eradication of invasive mice at Marion Island, as well as as investigate the impacts of non-native species at the Falkland Islands (Malvinas).
Best practice guidelines for reducing risk of disease outbreaks at islands are being developed by the Agreement on the Conservation of Albatrosses and Petrels. Once available, these guidelines should be implemented.
The impact of any proposed fishery on the prey of Gentoo Penguins should be carefully assessed before such a fishery is allowed. Consideration should be given to declaring marine protected areas at important feeding grounds of gentoo penguins.
Identification 51-90 cm. The third largest penguin, although body size is highly variable across its range. Males typically larger than females. Black face, head and back. Conspicuous, but variable, white patches above eyes, typically meeting across the crown. Bright red-orange bill with black along the upper mandible and at the tip. Feet, pale whitish-pink to red.
Text account compilers
Moreno, R., O'Brien, A., Pearmain, L., Everest, J., Trathan, P. N., McClellan, R., Martin, R.
Ballard, G., Barbraud, C., Bost, C., Cimino, M., Crawford, R.J.M., Croxall, J., DuBois, L., Fraser, W., García Borboroglu, P., Herman, R., Hinke, J., Humphries, G., Lynch, H., Makhado, A., Schmidt, A., Schneider, T., Stanworth, A., Symes, A. & Trathan, P. N.
BirdLife International (2021) Species factsheet: Pygoscelis papua. Downloaded from http://www.birdlife.org on 21/04/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/04/2021.