Using spatial resampling to assess redd count survey length requirements for Pacific Lamprey

North American Journal of Fisheries Management
By: , and 



Pacific Lamprey Entosphenus tridentatus has declined across its range along the West Coast of North America, and an understanding of all life history phases is needed to address population recovery. Spawning surveys (redd counts) are common tools currently used to monitor returning adult salmonids, but such methodologies are in their infancy for Pacific Lamprey. Our objective was to assess the minimum spawning survey distance required to detect the presence of Pacific Lamprey redds and obtain precise redd density estimates from these data. To do this, we statistically resampled existing spawning locations of Pacific Lamprey collected during spawning surveys in four streams of the Willamette River Basin, Oregon, during spring of 2013. We found that the minimum survey distance for Pacific Lamprey redd detection was inversely related to the observed redd density and was always less than 1.2 km. Survey distance requirements to obtain precise redd counts (±20% of observed redd densities) were also inversely related to redd density and habitat availability, and varied between 1.3 km and 13.7 km. Our results suggest that spawning surveys are a potential tool for monitoring adult Pacific Lamprey abundance, but the specific objectives of the monitoring programs and acknowledgment of unknowns must be considered prior to implementation into recovery plans.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Using spatial resampling to assess redd count survey length requirements for Pacific Lamprey
Series title North American Journal of Fisheries Management
DOI 10.1080/02755947.2014.932867
Volume 34
Issue 5
Year Published 2014
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Seattle
Description 9 p.
First page 923
Last page 931
Country United States
State Oregon
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