Polaris, Dipper and the Death of the Southern Resident Killer Whales: Part 5: Lack of Food


Polaris, Dipper and the Death of the Southern Resident Killer Whales:

Part 5: Lack of Food

Guest Blogger: Courtney Halvorson

In the wintertime Southern Resident orca have been observed waiting at the mouth of the Columbia River... waiting for a salmon return that is no longer coming.

Dams have been preventing precious Chinook salmon populations from returning and successfully spawning in watersheds for over 100 years. There are over 600 of these dams in the United States and 400 in Canada, which directly affect the water flow into the Salish Sea. Without successful spawning events each year salmon populations will continue to decline. Present Salmon runs from the Columbia Basin are only 5-10% of historical numbers and this is keeping the critically endangered Southern Resident killer whales from proper nutrition.

Currently 4 dams sit on the lower Snake River preventing the large majority of precious Chinook from spawning. The dams now cost more to operate than the energy that they generate. The easiest, most cost efficient and immediate relief for the killer whales is breaching these dams by bypass channels, which will move water and salmon around the concrete structures.

This graph represents trends in each Chinook salmon run in the region along with the population of Southern Resident Killer Whales. Note: any drop in salmon abundance correlates with SRKW population decrease. Chart courtesy of Jane Cogan 2015 and is based on data from the Center for Whale Research, the Pacific Fishery Management Council, NOAA Technical Memorandum NMFS-NWFSC-123 and the Pacific Salmon Commission.

While the decline in Chinook salmon is correlated with the rise in dams, overfishing and salmon habitat degradation likely play influential roles in the decline of food for Southern Resident Killer Whales. Pollution may also play a role in the decreasing size of Chinook salmon over the years; as southern resident killer whales prefer the largest, fattest Chinook, this would have serious consequences for the whales. Therefore, it is vital that fisheries are well managed and fish habitat, including the species supporting the Chinook salmon, are protected.

Ken Balcomb, head researcher at the Center for Whale Research, predicts that a pairing of starvation and septicemia eventually took Polaris’s life. We have a population of skinny whales and we are going to be reading many more obituaries in the next few years unless we start doing something now. We have lost 5 whales since January 2015 (J55, L120, J14, J28 and J54).

No fish, no blackfish.

Stay tuned for our final segment exploring what we can do to help protect our Southern Resident Killer Whales.

Courtney Halvorson is a PNW educated Marine Biologist, Wildlife Photographer and Marine Naturalist for Orca Spirit Adventures in Victoria, British Columbia.