Proposed Abstract Title

Phocoenacide – The Killing of Harbor Porpoise (Phocoena phocena) by Fish Eating Southern Resident Killer Whales (Orcinus orca).

Presenter/Author Information

Deborah Giles, Center for Whale ResearchFollow

Type of Presentation

Oral

Session Title

General species and food webs

Location

2016SSEC

Description

Southern Resident fish-eating killer whales have been observed "mugging" and killing harbor porpoise without subsequent predation on the animal carcass. While occasional porpoise killings by L-pod and K-pod members had been documented by staff of the Center for Whale Research since regular monitoring started in 1976, prior to 2005, J-pod was never seen engaging in this “mugging” behavior. However, in 2005, multiple different members of J-pod were documented killing harbor porpoises on four separate occasions during the month of July. Since 2005, several different research groups have recorded additional mugging episodes by members of all three Southern Resident Killer Whale pods. Pooling long-term datasets from myriad research groups 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.

Comments

This research is a collaborative project with researchers from the Center for Whale Research, The Whale Museum, The SeaDoc Society, Cascadia Research Collective, NOAA - Northwest Fisheries Science Center and Canadian Department of Fisheries and Oceans.

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Phocoenacide – The Killing of Harbor Porpoise (Phocoena phocena) by Fish Eating Southern Resident Killer Whales (Orcinus orca).

2016SSEC

Southern Resident fish-eating killer whales have been observed "mugging" and killing harbor porpoise without subsequent predation on the animal carcass. While occasional porpoise killings by L-pod and K-pod members had been documented by staff of the Center for Whale Research since regular monitoring started in 1976, prior to 2005, J-pod was never seen engaging in this “mugging” behavior. However, in 2005, multiple different members of J-pod were documented killing harbor porpoises on four separate occasions during the month of July. Since 2005, several different research groups have recorded additional mugging episodes by members of all three Southern Resident Killer Whale pods. Pooling long-term datasets from myriad research groups 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.