Advances in remote sensing of emperor penguins: first multi-year time series documenting trends in the global population.

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 modelling, we estimated a comprehensive population trajectory over a recent 10-year period, encompassing the entirety of the species' range.

Insights from the first global population estimate of Weddell seals in Antarctica.

The Weddell seal is one of the best-studied marine mammals in the world, owing to a multidecadal demographic effort in the southernmost part of its range. Despite their occurrence around the Antarctic coastline, we know little about larger scale patterns in distribution, population size, or structure. We combined high-resolution satellite imagery from 2011, crowd-sourcing, and habitat modeling to report the first global population estimate for the species and environmental factors that influence its distribution.

Ice matters: Life-history strategies of two Antarctic seals dictate climate change eventualities in the Weddell Sea.

The impacts of climate change in Antarctica and the Southern Ocean are not uniform and ice-obligate species with dissimilar life-history characteristics will likely respond differently to their changing ecosystems. We use a unique data set of Weddell Leptonychotes weddellii and crabeater seals' (CESs) Lobodon carcinophaga breeding season distribution in the Weddell Sea, determined from satellite imagery. We contrast the theoretical climate impacts on both ice-obligate predators who differ in life-history characteristics: CESs are highly specialized Antarctic krill Euphausia superba predators and breed in the seasonal pack ice; Weddell seals (WESs) are generalist predators and breed on comparatively stable fast ice.

Coping with the loss of large, energy-dense prey: a potential bottleneck for Weddell Seals in the Ross Sea.

Extraction of Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea began in 1997, following a management plan that targets the largest fish with a goal of reducing the spawning biomass by 50% over 35 yr. We investigate the potential long-term consequences of the reduced availability of this prey for Weddell seals (Leptonychotes weddellii). Energy demands in seals are acute, especially immediately following lactation, when females must recover substantial mass and cope with molting costs.