Hundreds of thousands of juvenile spring chinook salmon died Monday at an Umpqua River fish hatchery after a clogged intake pipe blocked their access to water.
A fish carcass caused the clog at the Rock Creek Hatchery near Roseburg by blocking the flow of water through a raceway.
According to a release from the Oregon Department of Fish and Wildlife, the clog didn’t limit flow enough to trigger an alarm. By the time an employee discovered the problem less than an hour later, hatchery manager Dan Meyer said, “it was barely a trickle.”
The water temperature in the raceway had risen to 68 degrees, stressing the fish and causing them to consume oxygen faster. With no water flowing through the raceway to replenish lost oxygen, levels of the dissolved gas fell to lethal levels.
As a result, all 400,000 of this year’s chinook died. The catastrophe will hit Umpqua River recreational fishers hard in 2018, when the largest portion of this year’s smolts would have returned upstream as adults.
