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Marine Biology

, Volume 161, Issue 6, pp 1361–1374 | Cite as

Linking marine predator diving behavior to local prey fields in contrasting habitats in a subarctic glacial fjord

  • Jamie N. Womble
  • Gail M. Blundell
  • Scott M. Gende
  • Markus Horning
  • Michael F. Sigler
  • David J. Csepp
Original Paper

Abstract

Foraging theory predicts that animals will adjust their foraging behavior in order to maximize net energy intake and that trade-offs may exist that can influence their behavior. Although substantial advances have been made with respect to the foraging ecology of large marine predators, there is still a limited understanding of how predators respond to temporal and spatial variability in prey resources, primarily due to a lack of empirical studies that quantify foraging and diving behavior concurrently with characteristics of prey fields. Such information is important because changes in prey availability can influence the foraging success and ultimately fitness of marine predators. We assessed the diving behavior of juvenile female harbor seals (Phoca vitulina richardii) and prey fields near glacial ice and terrestrial haulout sites in Glacier Bay (58°40′N, −136°05′W), Alaska. Harbor seals captured at glacial ice sites dived deeper, had longer dive durations, lower percent bottom time, and generally traveled further to forage. The increased diving effort for seals from the glacial ice site corresponded to lower prey densities and prey at deeper depths at the glacial ice site. In contrast, seals captured at terrestrial sites dived shallower, had shorter dive durations, higher percent bottom time, and traveled shorter distances to access foraging areas with much higher prey densities at shallower depths. The increased diving effort for seals from glacial ice sites suggests that the lower relative availability of prey may be offset by other factors, such as the stability of the glacial ice as a resting platform and as a refuge from predation. We provide evidence of differences in prey accessibility for seals associated with glacial ice and terrestrial habitats and suggest that seals may balance trade-offs between the costs and benefits of using these habitats.

Keywords

Prey Availability Terrestrial Habitat Harbor Seal Walleye Pollock Humpback Whale 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

Funding and logistical support for this project was provided by the National Park Service (NPS)—Coastal Cluster Program, Glacier Bay National Park and Preserve, NPS-NRPP (PMIS Project # 35747), Alaska Department of Fish and Game Marine Mammal Program funded by congressional appropriations administered via grants from the National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center-Auke Bay Laboratory, Alaska Sealife Center, and the Ocean Alaska Science and Learning Center. We sincerely thank Justin Smith (R/V Capelin), Dan Foley (R/V Steller), and Jacques Norvell (Tal Air) for safe and expert pilotage at sea and in the air. We greatly appreciate the efforts of numerous individuals (Jason Herreman, John Wells, Suzanne Conlon, Lori Polasek, Jill Prewitt, Natalie Bool, Trevor Ose, Rachel Dziuba, Shawna Karpovich, Randy Naylor, Christine Schmale, Dave Withrow, Dennis McAllister, Jennifer Burns, Jay VerHoef, Kevin White) that provided assistance with harbor seal capture and tagging efforts. J.N.W. was supported by a Mamie Markham Research Fellowship (OSU-Hatfield Marine Science Center), Munson Wildlife Fellowship, Oregon State University (OSU) Laurels Fellowship, Horace M. Albright-Conrad L. Wirth Fellowship, the OSU Marine Mammal Institute-Pinniped Ecology Applied Research Laboratory, NRAC Professional Development Grants, the NPS- Coastal Cluster Program, and Glacier Bay National Park and Preserve. Lorenzo Ciannelli, Clint Epps, Mary-Anne Lea, Dawn Wright, and three anonymous reviewers provided useful comments and discussions on previous versions of the manuscript. The findings and conclusions in the paper are those of the authors and do not necessarily represent the views of the National Marine Fisheries Service. Reference to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA. All harbor seal capture, handling, and research were conducted under Marine Mammal Protection Act (MMPA) permit numbers 358-1787-00 and 358-1787-01 issued to Alaska Department of Fish and Game by NOAA’s Protected Resources Division. Harbor seal capture, handling, and research were also authorized by Glacier Bay National Park under Scientific Research and Collecting permit numbers GLBA-2004-SCI-0003, GLBA-2005-SCI-0003, GLBA-2006-SCI-0003, GLBA-2007-SCI-0003, and associated Glacier Bay National Park and Preserve Waivers to park regulations. Animal use protocols used in this research were reviewed and approved by the Institutional Animal Care and Use Committee at the State of Alaska Department of Fish and Game (protocol 07-16).

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Copyright information

© Springer-Verlag Berlin Heidelberg (outside the USA) 2014

Authors and Affiliations

  • Jamie N. Womble
    • 1
    • 2
  • Gail M. Blundell
    • 3
  • Scott M. Gende
    • 2
  • Markus Horning
    • 1
  • Michael F. Sigler
    • 4
  • David J. Csepp
    • 4
  1. 1.Department of Fisheries and Wildlife, Marine Mammal Institute, Hatfield Marine Science CenterOregon State UniversityNewportUSA
  2. 2.Glacier Bay Field StationNational Park ServiceJuneauUSA
  3. 3.Division of Wildlife ConservationAlaska Department of Fish and GameDouglasUSA
  4. 4.National Marine Fisheries Service, Alaska Fisheries Science CenterNational Oceanic and Atmospheric AdministrationJuneauUSA

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