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Plos Biology Template
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  • Katelyn Woddail,
  • Katherine Beck
Katelyn Woddail
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Katherine Beck


Modern brush-tailed penguins, consisting of Adelie (Pygoscelis adeliae), chinstrap (Pygoscelis antarcticus), and gentoo penguins (Pygoscelis papua), have a single primary food source: krill. More specifically, Antarctic krill (Euphausia superba) make up the majority of their diets. Krill play an important role in in the global marine food web, serving as major food sources for small fish and seabirds as well as cetaceans and pinnipeds \cite{NICOL_2006}. As Antarctica and nearby islands in the Southern Ocean, such as South Georgia Island, are known to be affected by glacial melting resulting from multiple anthropogenic and cyclical stressors, populations of krill may be affected \citep{Rignot_2013,Pritchard_2012,Chen_2013}. In turn, brush-tailed penguin populations could suffer unless another food source was exploited. Using yearly count observations of brush-tail penguin nests from the Antarctic Western Peninsula along with yearly haul estimates of E. superba, population data were analyzed for significant trends and correlations over extended timescales. Although there were some observable trends and significant differences in the means of late-19th and early-20th century population estimates of both E. superba and P. adeliae, there were no significant correlations or regressions among any of the species. With these results, we question the accuracy of using haul counts as a proxy for population size as well as potential distribution shifts rather than abundance changes. There are also potential seasonal and anomaly-related variables which were not accounted for, like sea ice recession and breeding seasons.