The importance of seasonal sea surface height anomalies for foraging juvenile southern elephant seals

• Published in: Marine Biology
• Main Authors: Tosh, Cheryl A., De Bruyn, P.J. Nico, Steyn, Jumari, Bornemann, Horst, Van der Hoff, John, Stewart, Brent S., Plotz, Joachim, Bester, Marthan Nieuwoudt
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2015
• Subjects: Importance of seasonal sea surface; Marion Island; Sea level anomaly (SLA); Southern elephant seals (SES); Antarctic; Alfred Wegener Institute; Antarc*; Australian Antarctic Division; Elephant Seals; South African National Antarctic Programme; Southern Elephant Seals
• Online Access: http://hdl.handle.net/2263/50390; https://doi.org/10.1007/s00227-015-2743-4

A novel classification system was applied to the sea level anomaly (SLA) environment around Marion Island. We classified the SLA seascape into habitat types and calculated percentage of habitat use of ten juvenile southern elephant seals (SES). Movements were compared to SLA and SLA slope values indicative of ocean eddy features. This classification provides a measure of habitat change due to seasonal fluctuations in SLA. Some of the seals made two migrations in different seasons, each of similar duration and proportions of potential foraging behaviour. The seals in this study did not use any intense eddy features, but their behaviours varied with SLA class. Potential foraging behaviour was positively influenced by negative SLA values (i.e. areas of below average sea surface height). Searching behaviour during the winter was more likely at eddy edges where high SLA slope values correlated with low SLA values. Though the seals did not forage within newly spawned eddies, they did forage near the sub-Antarctic front. Plankton and other biological resources transported by eddies formed at the subtropical convergence zone are evidently concentrated in this region and enhance the food chain there, forming a foraging ground for juvenile SES from Marion Island. The Alfred Wegener Institute for Polar and Marine Research (Germany), the Department of Science and Technology through the National Research Foundation (South Africa), the Department of Environmental Affairs via the South African National Antarctic Programme, the Australian Antarctic Division and Hubbs- SeaWorld Research http://link.springer.com/journal/227 2016-10-31 hb2015