Pacific lamprey (Entosphenus tridentatus) populations throughout the Columbia River Basin (CRB) are in decline.  Multiple reasons for the decline have been identified including passage at mainstem CRB dams and habitat degradation; however, little is known about limiting factors within CRB tributaries.  Declining lamprey populations is of primary concern to the Confederated Tribes of the Warm Springs Reservation of Oregon (CTWSRO) due to their significant cultural and ecological value.  Accordingly, the project intent is to expand knowledge of lamprey populations and factors limiting production in the Deschutes and Hood rivers as well as Fifteenmile Creek subbasins.  The ultimate project goal is to establish, conserve and/or maintain harvestable populations for perpetuity.  

Prior to the project 2002-016-00, little was known about Pacific lamprey in the Deschutes River Subbasin.  To date knowledge of Pacific lamprey in lower Deschutes River Subbasin has been greatly expanded including distribution information (overwintering, spawning, juvenile), abundance in the form of yearly escapement estimates, habitat requirements (adult and juvenile); however, key pieces of information are missing such as primary limiting factors to production and causes for decline in juvenile distribution.  

Seufert Falls (rkm 0.4) on Fifteenmile Creek is an important Pacific lamprey harvest location for CTWSRO tribal members; yet little information is available on their status.  Habitat conditions (e.g., low flows, high water temperatures) in Fifteenmile is likely the largest, in subbasin, factor limiting reproduction.  

Likewise, very little is known about historical or current distribution of Pacific lamprey in the Hood River Subbasin.  Lamprey were once widely distributed throughout the Hood River basin (USFS 1996); however, lack of adequate passage facilities at Powerdale Dam (rkm 7.2) is believed to have eradicated lamprey from areas upstream.  With the removal of Powerdale Dam in summer 2010, we will investigate Pacific lamprey recolonizations upstream of the dam.
This project (2011-014-00) combines projects 2002-016-00 and 2007-007-00.  The contract period is 10/1/2014 - 09/30/2015.  Project objectives are consistent with those identified by the Columbia Basin Pacific Lamprey Technical Work Group (CBPLTWG).