Monitoring adult Pacific lamprey (Lampetra tridentata) migration behavior in the lower Columbia River using radiotelemetry, 1998-1999

Pacific lamprey (Lampetra tridentata) abundance in the Columbia River Basin has declined significantly since the 1960s. We used radiotelemetry to document adult lamprey migration behavior at Columbia River Basin hydroelectric facilities and to identify factors affecting their successful return to spawning areas. Radiotelemetry has been used to study anadromous fish behavior for many years and has been used for lamprey research in the Columbia River for the past 4 years. In 1998 and 1999, we evaluated the behavior ofradio-tagged Pacific lamprey in the lower Columbia River Basin, primarily at Bonneville Dam. Our objectives were: 1) to determine routes of passage at hydroelectric dams, 2) to identify locations in the fishways where lamprey fail to advance, and 3) to test the effects ofspillway entrance modifications on lamprey entry into the fishways at Bonneville Dam. Contract no. E96950021