File Entry: Sensitivity of resident killer whale population dynamics to Chinook salmon abundance file

Sensitivity of resident killer whale population dynamics to Chinook salmon abundance.

L. Antonio Vélez-Espino1,£, John K.B. Ford2, Charles K. Parken1, Graeme Ellis2, Eric Ward3, Larrie LaVoy4, Ken Balcomb5, M. Bradley Hanson3, Dawn P. Noren3, Tom Cooney4, Rishi Sharma6,7.
(1) Salmon and Freshwater Ecosystems Division, Fisheries and Oceans Canada; (2) Marine Mammal Division, Fisheries and Oceans Canada; (3) Conservation Biology Division, Northwest Fisheries Science Center (NOAA); (4) Salmon Management Division, Northwest Region (NOAA); (5) Center for Whale Research, WA; (6) Columbia River Inter-Tribal Fish Commission; (7) Current: Indian Ocean Tuna Commission.

Two distinct populations of resident killer whales (Orcinus orca) in the northeastern Pacific Ocean have been listed in Canada and the U.S. as of conservation concern. The Southern Resident Killer Whale (SRKW) population is currently listed as endangered in both countries. The Northern Resident Killer Whale (NRKW) population has been listed as threatened in Canada. The major threats recognized for these two populations are nutritional stress associated to prey abundance levels and availability, pollution and contaminants, and disturbances from vessels and sound. An important difference in the
population dynamics of these two populations is that, in spite of their home range overlap and potential access to similar resources, SRKW has remained at a population size of less than 100 individuals for the last four decades with an average of 85 individuals in the last decade whereas NRKW’s population size has been generally increasing for the last 4 ecades with 268 individuals at the end of 2011.