Using animal telemetry data to identify areas of ecological significance in the Southern Ocean
Robert Harcourt

Authors

R Harcourt
Graduate School of Environment, Macquarie University

C Guinet
Centre National de la Recherche Scientifique

S Bestley
Australian Antarctic Division

J Charrassin
Muséum National d'Histoire Naturelle

SD Goldsworthy
Marine Environment and Ecology, SAARDI Aquatic Sciences

M Lea
Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia

CR McMahon
Research Institute for the Environment and Livelihoods, Charles Darwin University

MA Hindell
Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia

Abstract

Far from homogeneous, the Southern Ocean is a complex mix of frontal regions, eddies, currents, and a dynamic sea-ice zone, all of which can act to concentrate nutrients and productivity in some areas and dissipate them in others. Establishing the physical and biological determinants of ecologically important areas is a core question in marine ecology, but our ability to do this is hampered by a lack of data collected at the appropriate spatial and temporal scales. However, animal tracking data can provide valuable insights. Predators focus their foraging efforts in regions that enable them to meet their energetic needs in the context of current and future requirements. Individual animal-borne CTD-SRDLs afford us the capacity to record physical attributes of areas of ecological importance to animals and interpret the effects structure and variability at-sea have on individual life history traits such as growth, reproduction and survival. The Integrated Marine Observing System (IMOS) and the French polar program is supporting tracking of several species in the Southern Ocean using CTD tags, which has so far provided more than 65,000 CTD profiles in the Southern Indian Ocean from 7 consecutive years (2007-2013) between Iles Kergeulen and Prydz Bay enabling a comprehensive spatial and temporal description of the ocean habitats used by the animals. Coupled with the movement and diving behaviour of the seals, these data identify modified shelf water and upper circumpolar deep water as important habitats. This information can be used to predict how seal foraging locations change with respect to changing Southern Ocean conditions.