Pacific Lamprey Assessment


Pacific Lamprey Assessment

Every four to five years the the Pacific Lamprey Conservation Initiative (PLCI) and its partners evaluate Pacific Lamprey habitat conditions, population demographics, distribution, and threats. This information is used to inform NatureServe, a diagnostic tool that characterizes conservation risks of Pacific Lamprey across their historical range.

The first Assessment was completed in 2011/2012 in preparation for Lamprey Summit III. Previous versions can be found here:


2022 Update

In 2022, PLCI and its Regional Management Units (RMUs) will be working with our partners to revise the Pacific Lamprey Assessment. The Assessment ranks population demographic and threat factors to describe the current species range and status, compares current to historical status, and calculates the relative risk to extirpation of Pacific Lamprey at the 4th field HUC watershed level.

In addition to information in the Pacific Lamprey Distribution Database, the local knowledge and expertise of each of PLCI’s 18 RMUs is pivotal to revising the Assessment. To support and inform the 2022 Assessment revision, each of the RMUs will be meeting in the coming months to discuss any major changes to the Assessment ranks and determine the final ranks to be entered into the NatureServe model based on their collective local knowledge.

In addition to the important updates to current information in the Assessment, in 2022 PLCI is especially hoping to address information gaps in Coastal Washington and Alaska. Interested stakeholders are invited to contribute to this process, and encouraged to reach out to RMU leads about upcoming meetings and other ways to participate.

Calculated NatureServe risk ranks for Pacific Lamprey (2018).

Evolution of the Assessment

The U.S. Fish and Wildlife Service (USFWS) hosted the Pacific Lamprey Conservation Initiative Work Session on October 28-29, 2008 in Portland, Oregon. The purpose of the Work Session was to bring managers and scientists with various skills and expertise together to facilitate communication on the current status and ongoing efforts to conserve Pacific Lamprey and to begin development of a collaborative, range-wide Conservation Plan.

The general objectives of the Work Session were:

  1. Develop an outline of existing knowledge, data, and information about Pacific Lamprey
  2. Identify uncertainties or knowledge gaps related to these topics.

The full proceedings of the 2008 Work Session can be accessed here.


Partner Assessments for Pacific Lamprey

Several partners have also worked to create Pacific Lamprey assessments outside of the Initiative process. These important documents supplement the analysis conducted for assessments listed above.

Tribal Pacific Lamprey Restoration Plan

Pacific Lamprey provided an important source of food for the tribes of the Columbia River Basin. Once returning to the Columbia River and its tributaries by the millions, approximately 48,000 returned to Bonneville Dam in 2011. To address this decline, the Columbia River treaty tribes created the most comprehensive plan for Pacific Lamprey that the Columbia Basin has seen. 

U.S. Army Corps of Engineers 10 Year Lamprey Plan

The goal is to identify specific actions that can be taken to improve lamprey passage at U.S. Army Corps of Engineers (USACE) dams along the lower Columbia and Snake rivers.

Oregon Department of Fish & Wildlife

The following include the Oregon Department of Fish and Wildlife (ODFW) 2005 Pacific Lamprey assessment sections from the Oregon Native Fish Status Report

Idaho Department of Fish & Game

In 2011, Idaho Department of Fish and Game conducted a status report on Pacific Lamprey in Idaho. 

    ©2022 Pacific Lamprey Conservation Initiative