Big Chinook Return! Small Spawning Results. Why is That?

Wednesday, Sept. 23, 2020: The forecasted chinook return to the Issaquah Salmon Hatchery was about 4,000 fish. The number counted through the Chittenden Locks was 12,780 as of 09/20. What?!? Historically, 50 to 70% of the fish counted through the Locks make it to the Issaquah hatchery. Some of the chinook are headed to the Cedar River, where they are considered an endangered population, but most are headed our way.

Another brush with reality: this time, the males outnumbered the females almost 3 to 1! We know that pinnipeds (and our beloved orcas) prefer female chinook – they are loaded with fat and protein-filled eggs, but this season that tendency is extreme.

The WDFW set a pretty high bar to assure the safety of the staff and volunteers at the spawning shed, but the shortfall of female chinook made it a short day, resulting in 328,000 fertilized eggs — a small but significant step to the 3,200,000 chinook egg goal for the year. The holding pond is full, the creek is full, so we are on a good path to meeting the goal.

What can we conclude from this?
Salmon return forecasting is even tougher than weather forecasting. And, we need to get good data on where the female attrition is happening, and whether something can be done about that.

~Larry Franks

Please note that the WDFW is not allowing tours on Tuesdays, spawning days, as keeping staff, volunteers and possible visitors safe is paramount.