University of California
California Fish Website

Fish Species


 Common Name Klamath River Lamprey
 Scientific Name Entosphenus similis
 Native Yes
 Identification
Klamath River lamprey. Captured attached to a brown trout from the upper Trinity River near river mile 85 on 22 July 2009. Total length: 27 cm. Photo courtesy of John Hileman, California Department of Fish and Game.
Klamath River lamprey. Captured attached to a brown trout from the upper Trinity River near river mile 85 on 22 July 2009. Total length: 27 cm. Photo courtesy of John Hileman, California Department of Fish and Game.

Klamath River lamprey, mouth. Captured attached to a brown trout from the upper Trinity River near river mile 85 on 22 July 2009. Photo courtesy of John Hileman, California Department of Fish and Game.
Klamath River lamprey, mouth. Captured attached to a brown trout from the upper Trinity River near river mile 85 on 22 July 2009. Photo courtesy of John Hileman, California Department of Fish and Game.

Klamath River lamprey, trunk myomeres. Blue arrows indicate section along which 63 trunk myomeres were counted. Photo courtesy of John Hileman, California Department of Fish and Game. Edited by Lisa Thompson, UC Davis.
Klamath River lamprey, trunk myomeres. Blue arrows indicate section along which 63 trunk myomeres were counted. Photo courtesy of John Hileman, California Department of Fish and Game. Edited by Lisa Thompson, UC Davis.

Brown trout with lamprey scar. Captured from the Trinity River on 29 July 2009. Photo courtesy of John Hileman, California Department of Fish and Game.
Brown trout with lamprey scar. Captured from the Trinity River on 29 July 2009. Photo courtesy of John Hileman, California Department of Fish and Game.

  • Small lamprey: 14-27 cm TL
  • Two dorsal fins
  • Body segments (myomeres): 58-65
  • Body coloration: dark body and lower oral hood, may have ridge of light pigmentation near tail
  • Oral disc length about 9% of TL, wider than head
  • Most prominent teeth of California lampreys
  • Supraoral lamina: 3 cusps
  • Transverse lingual lamina (tongue plate): 20-29 cusps
  • Four inner lateral plates on both sides: (bicuspid-tricuspid-tricuspid-bicuspid)
  • Anterior field above mouth:13 teeth
  • Posterior field below mouth:18 teeth
 Life History Klamath River Lampreys have not been fully studied and documented. Fish biologists know that they occupy the Klamath River and nearby reservoirs and lakes, where they live a predatory lifestyle. Klamath River Lampreys have been observed in the Upper Klamath River and Upper Klamath Lake, as well as the lower Klamath and Trinity Rivers and tributaries.

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