1. Michael Ford, a biologist with the National Marine Fisheries Service in Seattle, studies genetic variability in chinook. Photos by Sandra Bancroft-Billings/The Spokesman-Review
2. A researcher adjusts a wire after inserting a radio transmitter into the mouth of a spring chinook at the Bonneville Dam.
3. Wanda Bennett sorts fish at Lower Granite Dam. Many of the fish are drugged, branded, tagged, then loaded onto a barge for a trip downstream.
4. University of Idaho researcher Rudy Ringe and helper Dennis Quaempts prepare to tag a chinook, which will be tracked as it moves through Columbia Basin dams.
5. Fish biologist Jeffrey G. Nelson monitors tanks holding young salmon on the barge Chinook as they ride down the Snake River.
6. The Corps of Engineers is testing this contraption, called a surface collector, designed to herd young salmon around Lower Granite Dam.
7. Bobby Johnson hustles down a corridor in the bowels of McNary Dam during an inspection of screens that protect fish from turbines.