Event Title

Phocoenacide: the killing of porpoise (Phocoenidae) by fish eating Southern Resident killer whales (Orcinus orca)

Presentation Abstract

Southern Resident fish-eating killer whales have been observed "mugging" and killing harbor and Dall’s porpoise without subsequent predation on the animal carcass. While occasional porpoise killings by L-pod and K-pod members were documented by staff of the Center for Whale Research since regular monitoring started in 1976, prior to 2005, J-pod was rarely seen engaging in this behavior. However, in 2005, multiple different members of J-pod were documented killing harbor porpoises on five separate occasions during the month of July alone. Since 2005, more than 25 additional mugging episodes by members of all three Southern Resident killer whale pods have been documented with members of J pod participating in more than half. We investigate the cultural transmission of this unusual behavior through the southern resident killer whale community. Pooling long-term datasets from myriad research groups and whale watching vessel naturalists allows for robust analysis of this novel behavior with the aim of understanding why this behavior is occurring as well as possible implications for the local harbor porpoise population, a population already targeted as prey by mammal eating killer whales (Bigg’s killer whales) in the area.

Session Title

Cumulative Effects on Southern Resident Killer Whales (Orcinus orca)

Conference Track

SSE9: Transboundary Management and Policy

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE9-452

Start Date

4-4-2018 2:30 PM

End Date

4-4-2018 2:45 PM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 4th, 2:30 PM Apr 4th, 2:45 PM

Phocoenacide: the killing of porpoise (Phocoenidae) by fish eating Southern Resident killer whales (Orcinus orca)

Southern Resident fish-eating killer whales have been observed "mugging" and killing harbor and Dall’s porpoise without subsequent predation on the animal carcass. While occasional porpoise killings by L-pod and K-pod members were documented by staff of the Center for Whale Research since regular monitoring started in 1976, prior to 2005, J-pod was rarely seen engaging in this behavior. However, in 2005, multiple different members of J-pod were documented killing harbor porpoises on five separate occasions during the month of July alone. Since 2005, more than 25 additional mugging episodes by members of all three Southern Resident killer whale pods have been documented with members of J pod participating in more than half. We investigate the cultural transmission of this unusual behavior through the southern resident killer whale community. Pooling long-term datasets from myriad research groups and whale watching vessel naturalists allows for robust analysis of this novel behavior with the aim of understanding why this behavior is occurring as well as possible implications for the local harbor porpoise population, a population already targeted as prey by mammal eating killer whales (Bigg’s killer whales) in the area.