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Adult Pacific Lamprey Trends and Abundance

Lower Columbia / Willamette Region

Adapted from Luzier, C.W., H.A. Schaller, J. K. Brostrom, C. Cook-Tabor, D.H. Goodman, R.D. Nelle, K. Ostrand, and B. Streif. 2011. Pacific Lamprey (Entosphenus tridentatus) Assessment and template for Conservation Measures. U.S. Fish and Wildlife Service, Portland, Oregon. 282 pp.

View trends and abundance by clicking on sub-regions. To view counts at the dam, click on green icon.

alt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_textalt_text Evaluating Pacific lamprey status and trends for many watersheds in the Lower Columbia River/Willamette region is difficult as there is a lack of targeted monitoring efforts, harvest records, and dam counts. Subsequently, managers and researchers have not been able to estimate the current abundance of adult Pacific lamprey. Relying on best professional judgment, expansions of data from other species, and partial surveys for a limited area of the watershed, managers and researchers have suggested that the short-term trend in abundance ranges from declining to very rapidly-severely declining. The long-term health of Pacific lamprey in the Lower Columbia River sub-region is potentially compromised by passage limitations, dewatering and flow management, stream and floodplain degradation, and water quality, threats that have been identified as the highest priority in this sub-region.