Rationale (Changed due to Genuine (recent))

The Prince Edward Islands population of Gentoo Penguin Pygoscelis papua satisfied criterion A2, with a measured population decreases of 74% not having ceased, the causes of decrease not being fully understood and possibly not reversible. In 2012, the number of mature birds at the Prince Edward Islands was probably less than 2 500 mature individuals and has decreased by greater than 20% in two generations, satisfying the criterion for regionally Endangered under criterion C1.

Distribution

The Gentoo Penguin has a circumpolar breeding distribution that ranges in latitude from Cape Tuxon on the Antarctic Peninsula (65°16'S) to the Crozet Islands (46°00'S) (Lynch 2013). The Prince Edward Islands, together with the Crozet Islands, are at the northern extremity of the species' range (Marchant and Higgins 1990).

Habitat View more ecological information

Population

The global population is c. 387 000 pairs (Lynch 2013). In 2012, 556 pairs of Gentoo Penguin were counted breeding at Marion Island; the estimate of numbers breeding from a model fitted to annual counts was 767 pairs (Department of Environmental Affairs unpubl. data). In 2003, an estimated 475 pairs bred at Prince Edward Island (Ryan et al. 2003). The overall population of Gentoo Penguins at the Prince Edward Islands in 2012 was estimated at 1 031-1 242 pairs or 2 062-2 484 breeding individuals. Confidence in this population estimate is high.

Population trend

Global populations are thought to have decreased substantially, although fluctuations make it difficult to ascertain long-term trends (Lynch 2013). At Marion Island, 1 345 pairs of Gentoo Penguin bred during 1974-1977 (Siegfried et al. 1978) and 888 pairs in 1984 (Adams and Wilson 1987). Numbers breeding at Marion Island have been counted annually since 1994 (Huyser 2000). About 1 350 pairs bred in 1994 and 1995. This decreased to less than 800 pairs in 2003, and then increased to c. 1 100 pairs in 2008 (Crawford et al. 2003, 2009). Numbers subsequently decreased to 556 pairs in 2012, the lowest value yet recorded (Department of Environmental Affairs, unpubl. data). Overall, numbers of Gentoo Penguins breeding at Marion Island decreased by 52% between 1994 and 2012, a period of 18 years or 2.1 generations. This is equivalent to 74% in three generations. Confidence in this population trend estimate is high.

Threats

At Marion Island, compared to other localities, the population, breeding success and meal size of Gentoo Penguins are small and the breeding season is protracted, suggesting numbers are limited by food (Adams and Klages 1989). Food availability may be influenced by environmental factors and probably affects onset of breeding and breeding success, which in instances has been too low to sustain the population of Gentoo Penguins at Marion Island (Crawford et al. 2003c). A recent decrease in Gentoo Penguins at Iles Kerguelen is likely related to reduced food availability (Lescroël and Bost 2006). Growing populations of Antarctic Fur Seals Arctocephalus gazella at Marion and Prince Edward islands (Bester et al. 2009) may inflict increased mortality on Gentoo Penguins. Subantarctic Skuas Stercorarius antarcticus and both species of giant petrels Macronectes spp. also prey on adults, eggs or chicks (Crawford et al. 2003, BM Dyer pers. obs.).

At Marion Island, Gentoo Penguins are easily disturbed by humans (Crawford et al. 2003), less so at Prince Edward Island where visitor numbers are extremely tightly controlled and are kept very low and infrequent. Abandonment of nests may result in eggs and young chicks dying from exposure or being taken by skuas, giant petrels or Lesser Sheathbills Chionis minor. By comparison, in maritime Antarctica, parties of visitors in the vicinity of a Gentoo Penguin colony did not influence predatory behaviour of skuas (Crosbie et al. 1999). Disease has caused sometimes heavy mortality of two other species of penguin at Marion Island (Cooper et al. 2009). Climate change could reduce the suitability of northern localities such as the Prince Edward Islands for breeding by Gentoo Penguins, whereas populations are expanding southwards and increasing at the southern extreme of their distribution (Lynch et al. 2008). Finally, Gentoo Penguins could be badly affected by oil spills.

Conservation

Underway

At Marion Island, breeding sites of Gentoo Penguins are listed according to the Prince Edward Islands Management Plan as Zone 4: the strictest conservation area, with no helicopter movement permitted overhead, no casual access and only limited research allowed. There are strict guidelines in place for offloading diesel. No access is allowed to Prince Edward Island except for bona fide research and conservation purposes every 4-5 years. The Prince Edward Islands are listed as a Ramsar Wetland of International Importance, as a Special Nature Reserve under the Environment Conservation Act (No 73 of 1989) and the Prince Edward Islands Management Plan 1996. The Prince Edward Islands Marine Protected Area was proclaimed in 2013.

Proposed

A Population and Habitat Viability Assessment (PHVA) is recommended, as is a Biodiversity Management Plan, culminating in a National Species Recovery Plan. Best-practice guidelines for reducing risk of disease outbreaks at islands are being developed by the Agreement on the Conservation of Albatrosses and Petrels. Overwintering teams should be given basic training in the rescue and rehabilitation of oiled penguins. 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.

Research

* It is necessary to know how many pairs of Gentoo Penguins now breed at Prince Edward Island, for which a winter visit to the island will be required.

* Information on age at first breeding, adult survival and losses to predators at Marion Island is needed for population modelling.

* Updated information on the diet and foraging behaviour of Gentoo Penguins at Marion Island, during both breeding and non-breeding seasons, also is needed.

* A difficult but important challenge is gaining an understanding of how food availability for Gentoo Penguins fluctuates.