There was also a recent article about big die-offs in a "lagoon" leading to a pink hatchery, with warm water being listed as the culprit. Last week, my sounder showed 60-degree surface water on the West Coast of Haida Gwaii, which was a warmer reading than I ever got at the same spot during the "Blob" summers.
The radical weather pattern last winter that pushed all of the rain and snow that the Pacific NW usually gets onto California might well have lowered the snow pack up the Yukon and many other rivers, and an early thaw and record warmth could easily be making parts of the river inhospitable to salmon.