Preferred, small-scale foraging areas of two Southern Ocean fur seal species are not determined by habitat characteristics

• Main Authors: Wege, Mia, P. De Bruyn, Hindell, Mark, Mary-Anne Lea, Marthán Bester
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: figshare 2019
• Subjects: 59999 Environmental Sciences not elsewhere classified; FOS Earth and related environmental sciences; Ecology; FOS Biological sciences; 69999 Biological Sciences not elsewhere classified; Inorganic Chemistry; FOS Chemical sciences; Antarctic; Southern Ocean; Antarc*; Antarctic Fur Seal; Antarctic Fur Seals
• Online Access: https://dx.doi.org/10.6084/m9.figshare.c.4663292.v1; https://springernature.figshare.com/collections/Preferred_small-scale_foraging_areas_of_two_Southern_Ocean_fur_seal_species_are_not_determined_by_habitat_characteristics/4663292/1

Abstract Background To understand and predict the distribution of foragers, it is crucial to identify the factors that affect individual movement decisions at different scales. Individuals are expected to adjust their foraging movements to the hierarchical spatial distribution of resources. At a small local scale, spatial segregation in foraging habitat happens among individuals of closely situated colonies. If foraging segregation is due to differences in distribution of resources, we would expect segregated foraging areas to have divergent habitat characteristics. Results We investigated how environmental characteristics of preferred foraging areas differ between two closely situated Subantarctic fur seal (Arctocephalus tropicalis) colonies and a single Antarctic fur seal (A. gazella) colony that forage in different pelagic areas even though they are located well within each other’s foraging range. We further investigated the influence of the seasonal cycle on those environmental factors. This study used tracking data from 121 adult female Subantarctic and Antarctic fur seals, collected during summer and winter (2009–2015), from three different colonies. Boosted Regression Tree species distribution models were used to determine key environmental variables associated with areas of fur seal restricted search behaviour. There were no differences in the relative influence of key environmental variables between colonies and seasons. The variables with the most influence for each colony and season were latitude, longitude and magnitude of sea-currents. The influence of latitude and longitude is a by-product of the species’ distinct foraging areas, despite the close proximity (