Adélie penguin population changes at Stranger Point: 19 years of monitoring

Abstract

The Adélie penguin (Pygoscelis adeliae) breeding population at Stranger Point, King George Island (25 de Mayo), increased in number from 1965/66 until 1980/81 after which it started to decrease almost continuously up to the present. A significant decrease in the number of breeding pairs and chicks crèched was observed between 1995/96 and 2013/14 (75% and 78%, respectively), although the rate of this decrease has slowed since 2006/07. Over the last seven years, larger interannual fluctuations were recorded in the number of breeding pairs and chicks in crèches, as well in the breeding success. The values for the index of breeding success during 2007/08, 2009/10 and 2012/13 were low and this parameter showed higher temporal fluctuation in the period 2007/08 to 2013/14. The reduction in breeding success and the number of chicks reared to crèche will unfavourably impact on future population size at Stranger Point through the reduction of new recruits. Although Adélie penguin population trends on the Antarctic Peninsula are linked to the marine environment variability (i.e. reduction in sea ice affecting the availability of prey), breeding success is also influenced by the amount of snow fall which has increased in recent years.

Variability and change in the west Antarctic Peninsula marine system: Research priorities and opportunities

“…Populations of icedependent Adélie and chinstrap penguins have declined significantly (e.g. Figure 14; Ducklow et al 2013;Hinke et al 2017a;Juares et al 2015;Trivelpiece et al 2011) and the only Emperor penguin colony at the WAP has been lost due to changes in seasonal sea ice duration (Trathan et al 2011). Southward shifts of the maritime climate, displacing the Antarctic climate, have also increased precipitation and snow accumulation, which reduces the survival of Adélie penguin chicks (Carlini et al 2009;Chapman et al 2011).…”

Glacial melting: an overlooked threat to Antarctic krill

“…Thus, due to the central role of krill in these regions, an increasing loss of krill would have a large impact on the functional biodiversity of coastal systems. If krill in coastal areas are increasingly affected by sediments and mortality removes a proportion of them from the water column, birds and mammals relying on krill will have higher energetic costs associated with fulfilling their nutritional demands; this effect has been observed for species such as the Adélie penguin 47 , the abundance of which has changed in the area around Potter Cove. In addition, the strong decrease in krill biomass since the mid-1970s has been attributed to the decrease in winter sea ice cover 33 .…”

A global population assessment of the Chinstrap penguin (Pygoscelis antarctica)

“…Popular hypotheses suggest that penguin populations are driven by krill availability, but krill biomass is broadly affected by climate change, krill fishing, and the recovery of whale and seal populations—the collective effects of which are difficult to disentangle from the perspective of penguin dynamics 8 , 15 – 17 . Other potential impacts, including tourism, extreme weather events, and disease outbreaks, may be important at local scales or for short periods of time, but are less compelling explanations for the widespread changes observed across the Antarctic penguins 3 , 18 , 19 .…”

“…dynamics 8,[15][16][17] . Other potential impacts, including tourism, extreme weather events, and disease outbreaks, may be important at local scales or for short periods of time, but are less compelling explanations for the widespread changes observed across the Antarctic penguins 3,18,19 .…”