Floods and Lack of Habitat Hurt Chinook, Good Weather Boosts Pinks

Fewer juvenile wild chinook migrated from the Puyallup River in 2007, likely because winter floods in the winter of 2006 washed away chinook redds – or nests – before the fish had a chance to emerge from the gravel. But, because of good weather this past winter, a record number of pink salmon are leaving the watershed.

The Puyallup Tribe of Indians counts outgoing salmon with a smolt trap in the lower Puyallup River, enabling them to estimate the productivity of the entire watershed. A smolt trap is a safe and effective way to capture and count juvenile salmon. Smolt refers to the term “smoltification,” a physiological process juvenile salmon undergo that allows them to migrate from fresh to salt water.

According to recently analyzed data, fewer than 10,000 wild chinook migrated from the Puyallup watershed last year, down from a peak of 60,000 fish in 2005. On the other hand, over 100,000 pink salmon have left the system so far this year.