Evaluate Habitat Use and Population Dynamics of Lampreys in Cedar Creek, Annual Report 2002.

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) and river lamprey (L. ayresi) 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. This annual report describes the activities and results of the third year of this project. Adult (n = 62), metamorphosed (n = 76), transforming (n = 4), and ammocoete (n = 315) stages of Pacific and western brook lamprey were examined in 2002. Lampreys were captured using adult fish ladders, lamprey pots, rotary screw traps, and lamprey electrofishers. In addition, fifty-four spawning ground surveys were conducted during which 124 Pacific lamprey and 13 western brook lamprey nests were identified. Stream gradient of spawning grounds were surveyed to better understand spawning habitat requirements