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Pacific lamprey (Lampetra tridentata) in the Columbia River Basin have declined to a remnant of their pre-1940s populations and the status of the western brook lamprey (L. richardsoni) is unknown. Identifying the biological and ecological factors limiting lamprey populations is critical to their recovery, but little research has been conducted on these species within the Columbia River Basin. This ongoing, multi-year study examines lamprey populations in Cedar Creek, Washington, a third-order tributary to the Lewis River. Adult (n = 40), metamorphosed (n = 116), transforming (n = 10), and ammocoete (n = 870) stages from both species were examined in 2000. Lamprey were captured using adult fish ladders, rotary screw traps, and lamprey electrofishers, and spawning ground surveys were conducted. US Forest Service level II and strategic point-specific habitat surveys were conducted to assess habitat requirements of both adult and larval lamprey. Multivariate statistics will be applied to determine relationships between abundance and habitat