Marine Biology

, Volume 161, Issue 2, pp 459–472

Spatial and social connectivity of fish-eating “Resident” killer whales (Orcinus orca) in the northern North Pacific

Authors

    • National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries ServiceNOAA
    • School of BiologyUniversity of Aberdeen
  • John W. Durban
    • National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries ServiceNOAA
    • Southwest Fisheries Science Center, National Marine Fisheries ServiceNOAA
  • David K. Ellifrit
    • Center for Whale Research
  • Janice M. Waite
    • National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries ServiceNOAA
  • Craig O. Matkin
    • North Gulf Oceanic Society
  • Chris R. Lunsford
    • Auke Bay Laboratories, Alaska Fisheries Science Center, National Marine Fisheries ServiceNOAA
  • Megan J. Peterson
    • School of Fisheries and Ocean SciencesUniversity of Alaska Fairbanks
  • Jay Barlow
    • Southwest Fisheries Science Center, National Marine Fisheries ServiceNOAA
  • Paul R. Wade
    • National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries ServiceNOAA
Original Paper

DOI: 10.1007/s00227-013-2351-0

Cite this article as:
Fearnbach, H., Durban, J.W., Ellifrit, D.K. et al. Mar Biol (2014) 161: 459. doi:10.1007/s00227-013-2351-0

Abstract

The productive North Pacific waters of the Gulf of Alaska, Aleutian Islands and Bering Sea support a high density of fish-eating “Resident” type killer whales (Orcinus orca), which overlap in distribution with commercial fisheries, producing both direct and indirect interactions. To provide a spatial context for these interactions, we analyzed a 10-year dataset of 3,058 whale photo-identifications from 331 encounters within a large (linear ~4,000 km) coastal study area to investigate the ranging and social patterns of 532 individually identifiable whales photographed in more than one encounter. Although capable of large-scale movements (maximum 1,443 km), we documented ranges generally <200 km, with high site fidelity across summer sampling intervals and also re-sightings during a winter survey. Bayesian analysis of pair-wise associations identified four defined clusters, likely representing groupings of stable matrilines, with distinct ranging patterns, that combined to form a large network of associated whales that ranged across most of the study area. This provides evidence of structure within the Alaska stock of Resident killer whales, important for evaluating ecosystem and fisheries impacts. This network included whales known to depredate groundfish from longline fisheries, and we suggest that such large-scale connectivity has facilitated the spread of depredation.

Copyright information

© Springer-Verlag Berlin Heidelberg (outside the USA) 2013