title: High sea surface temperatures driven by a strengthening current reduce foraging success by penguins.
abstract: The world's oceans are undergoing rapid, regionally specific warming. Strengthening western boundary currents play a role in this phenomenon, with sea surface temperatures (SST) in their paths rising faster than the global average. To understand how dynamic oceanography influences food availability in these ocean warming "hotspots", we use a novel prey capture signature derived from accelerometry to understand how the warm East Australian Current shapes foraging success by a meso-predator, the little penguin. This seabird feeds on low trophic level species that are sensitive to environmental change. We found that in 2012, prey capture success by penguins was high when SST was low relative to the long-term mean. In 2013 prey capture success was low, coincident with an unusually strong penetration of warm water. Overall there was an optimal temperature range for prey capture around 19-21 °C, with lower success at both lower and higher temperatures, mirroring published relationships between commercial sardine catch and SST. Spatially, higher SSTs corresponded to a lower probability of penguins using an area, and lower prey capture success. These links between high SST and reduced prey capture success by penguins suggest negative implications for future resource availability in a system dominated by a strengthening western boundary current.
authors.affiliation: Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney NSW 2109, Australia.
authors.forename: Gemma
authors.initials: G
authors.lastname: Carroll
authors.affiliation: Evolution &Ecology Research Centre, School of Biological Earth and Environmental Sciences, University of New South Wales, Sydney NSW 2052, Australia.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Everett
authors.affiliation: Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney NSW 2109, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Harcourt
authors.affiliation: Taronga Conservation Society Australia, Bradleys Head Rd Mosman, Sydney NSW 2088, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Slip
authors.affiliation: Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney NSW 2109, Australia.
authors.forename: Ian
authors.initials: I
authors.lastname: Jonsen
mesh_terms: D000818:Animals; D004777:Environment; D009517:New South Wales; D009791:Oceanography; D011235:Predatory Behavior; D012623:Seawater; D062206:Spatial Analysis; D046429:Spheniscidae; D013696:Temperature