Evaluate Status of Pacific Lamprey in the Clearwater River and Salmon River Drainages, Idaho, 2009 Technical Report.

ABSTRACT The Pacific lamprey Lampetra tridentata is a native Snake River basin fish species occupying a unique ecological niche. The recent decline in numbers of returning Pacific lamprey adults to the Snake River basin has focused attention on the species. In 2000–2002, we employed electrofishing surveys to determine habitat utilization and distribution of Pacific lamprey ammocoetes in Red River, South Fork Clearwater River drainage, Idaho. Ammocoete average densities were 25.7/100 m2 in scour pools, 4.4/100 m2 in riffles, 2.1/100 m2 in rapids, and 253.3/100 m2 in the one alcove sampled. Ammocoetes were found in water depths ranging from 1.0 cm to 1.0 m; however, the two greatest densities were observed in habitat units with maximum depths greater than 0.50 m. Pacific lamprey ammocoete density decreased with increased velocity and coarse substrate, and increased with fine and medium substrates and riparian shade.

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Biology, Management, and Conservation of Lampreys in North America

Biology, Management, and Conservation of Lampreys in North America ◽

10.47886/9781934874134.ch15 ◽

2009 ◽

Keyword(s):

United States ◽

Life History ◽

Fish Species ◽

The United States ◽

Negative Effects ◽

The West ◽

Pacific Lamprey ◽

The Pacific ◽

River Drainages ◽

Management And Conservation

Abstract.—Efforts to minimize negative effects to fish species during instream activities generally do not consider the life history characteristics of native nongame fish species, particularly lamprey. While there is still much to be learned about Pacific lamprey Entosphenus tridentatus (formerly Lampetra tridentata) distribution, abundance, and status, the need to actively conserve lampreys is evident. Populations of the Pacific lamprey have been reduced in many river drainages along the West Coast of the United States. The purposes of this paper are to raise awareness of the need to consider Pacific lampreys in project implementation and to stimulate development of methods to address instream project impacts.

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