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Foraging behavior of northern fur seals closely matches the hierarchical patch scales of prey

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Title Foraging behavior of northern fur seals closely matches the hierarchical patch scales of prey
Names Benoit-Bird, Kelly J. (creator)
Battaile, Brian C. (creator)
Nordstrom, Chad A. (creator)
Trites, Andrew W. (creator)
Date Issued 2013-04-08 (iso8601)
Note This is the publisher’s final pdf. The published article is copyrighted by Inter-Research and can be found at: http://www.int-res.com/home/.
Abstract Marine prey often occur in hierarchical mosaics whereby small, high-density patches
are nested inside of larger, lower density aggregations. We tested the extent to which the foraging
behavior of a marine predator (northern fur seal Callorhinus ursinus) could be explained by the
hierarchical patch structure of a dominant prey species (juvenile walleye pollock Theragra chalcogramma)
in the eastern Bering Sea. Comparing the movements of satellite-tracked fur seals with
ship-based acoustic surveys of prey revealed that fur seals did not randomly search for prey, but
instead showed deviations in the distribution of step-lengths (distances between their foraging
patches) corresponding to the distances between aggregations of prey. Scales of prey distribution
varied between Bering Sea shelf and deep-water slope habitats, while spatial scale distributions
of fur seals showed corresponding changes, indicating that their search strategies were not innate
patterns decoupled from the environment. Fur seals tended to avoid the smallest prey patches in
both shelf and slope habitats. They also avoided prey patches that were separated by large distances.
Fur seals responded to several levels of prey patchiness simultaneously, resulting in strong
correlations between predator and prey over the entire range of aggregation scales observed in
juvenile pollock. Our results indicate that, despite having a varied diet, fur seal foraging paths
were defined by juvenile pollock aggregations. The presence of hierarchical, scale-dependent
aggregation in both predator and prey provides new insights into fur seal behavior and a means
to predict the dynamics of their interactions with prey.
Genre Article
Topic Patchiness
Identifier Benoit-Bird, K., Battaile, B., Nordstrom, C., & Trites, A. (2013). Foraging behavior of northern fur seals closely matches the hierarchical patch scales of prey. Marine Ecology Progress Series, 479, 283-302. doi:10.3354/meps10209 (http://www.int-res.com/articles/meps_oa/m479p283.pdf))

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