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https://komonews.com/news/local/scientists-id-another-possible-threat-to-orcas-pink-salmon
Over the years, scientists have identified dams, pollution and vessel noise as causes of the troubling decline of the Pacific Northwest's resident killer whales. Now, they may have found a new and more surprising culprit: pink salmon.
Four salmon researchers were perusing data on the website of the Center for Whale Research, which studies the orcas, several months ago when they noticed a startling trend: that for the past two decades, significantly more of the whales have died in even-numbered years than in odd years.
In a newly published paper, they speculate that the pattern is related to pink salmon, which return to the Salish Sea between Washington state and Canada in enormous numbers every other year — though they're not sure how. They suspect that the huge runs of pink salmon, which have boomed under conservation efforts and changes in ocean conditions in the past two decades, might interfere with the whales' ability to hunt their preferred prey, Chinook salmon.
Given the dire plight of the orcas, which officials say are on the brink of extinction, the researchers decided to publicize their discovery without waiting to investigate its causes.
(Score: 0) by Anonymous Coward on Sunday January 20 2019, @03:52PM (2 children)
https://www.int-res.com/abstracts/meps/v608/p291-296/ [int-res.com]
(Score: 0) by Anonymous Coward on Sunday January 20 2019, @10:00PM
Appreciate the link; thanks.
(Score: 0) by Anonymous Coward on Sunday January 20 2019, @10:54PM
Also found this
https://www.nationalgeographic.com/animals/2018/08/orcas-killer-whales-endangered-cetaceans-news/ [nationalgeographic.com]
What’s hurting them is, above all, the lack of available prey. The Columbia and Sacramento Rivers have been dammed, and we’ve seen a massive fall in Chinook salmon runs. Other threats include pollution, growing marine traffic and the controversial expansion of the oil pipeline close to Vancouver. Southern Residents don’t just rely primarily on Chinook salmon; they overwhelmingly rely on Chinook salmon from the Fraser River. And the Trans Mountain Pipeline, which has just been taken over by the Canadian government, threatens salmon production and access to that river.