Polychaete Infection Prevalence in the Klamath River FY2014

Salmonid Research, Monitoring, and Evaluation (RM&E)

Project IDYUROK-2014-2 PIPKR
Recovery DomainsN CA - S Oregon
Start Date06/01/2015
End Date09/30/2016
Last Edited05/08/2024
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We determined myxozoan infection rates, life cycle dynamics, and relative abundance of polychaete worms at an index site in the mainstem Klamath River over a 12 month period. This project helped monitor the efficacy of management action to reduce the myxozoan disease infectivity of the Klamath River. This study was a continuation of an in-depth multi-year study of polychaete worm (a key fish disease vector) infection rates, life cycle dynamics, and relative abundance in the Klamath River. Fish disease has been identified as a key limiting factor for both Chinook salmon (a primary target species for Tribal fisheries) and coho salmon (listed as Threatened under the ESA). This study was conducted in the upper reaches of the Klamath River near Iron Gate Dam in the areea of maximum salmonid infection using an alternative method of individual examination to provide more detailed and accurate data. This study allowed for analysis of inter-annual variation in infectivity rates and distribution of polychaete worm host organisms. Myxozoan parasites (Ceratomyxa shasta and Parvicapsula minibicornis) in the Klamath River kill an unacceptably high percentage of juvenile salmonid every year, including ESA listed coho salmon. These myxozoan parasites are dependent on the freshwater polychaete worm Manyunkia speciosa in addition to salmonid fishes to complete their life cycle. Determining and evaluating effective management actions to reduce myxozoan disease mortality in juvenile salmonids in the KLamath River requires a more complete understanding of the life cydle, dynamics, distribution, and infection dynamics of polychaetes. In particular, accurately determining the in-river life cycle, relative abundance, and infection rates of polychaetes prior to and after any management actions is of crucial importance. This study helped with the above mentioned goals.

Project Benefit    

Outcomes and benefits ar to provide data so that management actions (primarily water management related to the operation of the federally owned Klamath Irrigation Project) can be improved with respect to their effect on anadromous fish in general, and particularly with respect to ESA-listed SONCC coho salmon and Chinook salmon important to the Yurok Tribes subsistence and commercial fisheries.


Metric Completed Originally

Funding Details

Report Total:$50,500

Project Map



  • Worksite Identifier: 39885372
  • Start Date:
  • End Date:
Area Description

No Area Description data was found for this worksite.

Location Information

  • Basin: Klamath (180102)
  • Subbasin: 18010206
  • Watershed:
  • Subwatershed:
  • State: California
  • Recovery Domain: N CA - S Oregon
  • Latitude: 41.894018628
  • Longitude: -122.922363281


  • Klamath Mountains Province Steelhead DPS
  • Southern Oregon/Northern California Coast Coho Salmon ESU
  • Upper Klamath / Trinity Rivers Chinook Salmon ESU
  • Southern Oregon / Northern California Coastal Chinook Salmon ESU




  • E.0 Salmonid Research, Monitoring, and Evaluation (RM&E)Y (Y/N)
    •      . . E.0.a RM&E Funding 50,500.00
    •      . . E.0.b
      Complement habitat restoration project
    •      . . E.0.c
      Project identified in a plan or watershed assessment.
    •      . . E.0.d.1 Number of Cooperating Organizations 2
    •      . . E.0.d.2
      Name Of Cooperating Organizations.
      Oregon State University
    •      . . E.0.e.1 Number of reports prepared 0
    •      . . E.0.e.2
      Name Of Report
      Prevalence of C. Shasta infection in Polychaete Worm Hosts in the Upper Klamath River Mainstem
    •      . . E.2 ResearchY (Y/N)
      •      . . . . E.2.a Research Funding 50,500.00
      •      . . . . E.2.b.7 Investigating fish health and/or disease/parasitesY (Y/N)
        •      . . . . . . E.2.b.7.a
          Key issues addressed by fish health and/or disease/parasites research