Evaluating single-pass catch as a tool for identifying spatial pattern in fish distribution

Journal of Freshwater Ecology
By: , and 



We evaluate the efficacy of single-pass electrofishing without blocknets as a tool for collecting spatially continuous fish distribution data in headwater streams. We compare spatial patterns in abundance, sampling effort, and length-frequency distributions from single-pass sampling of coastal cutthroat trout (Oncorhynchus clarki clarki) to data obtained from a more precise multiple-pass removal electrofishing method in two mid-sized (500–1000 ha) forested watersheds in western Oregon. Abundance estimates from single- and multiple-pass removal electrofishing were positively correlated in both watersheds, r = 0.99 and 0.86. There were no significant trends in capture probabilities at the watershed scale (P > 0.05). Moreover, among-sample variation in fish abundance was higher than within-sample error in both streams indicating that increased precision of unit-scale abundance estimates would provide less information on patterns of abundance than increasing the fraction of habitat units sampled. In the two watersheds, respectively, single-pass electrofishing captured 78 and 74% of the estimated population of cutthroat trout with 7 and 10% of the effort. At the scale of intermediate-sized watersheds, single-pass electrofishing exhibited a sufficient level of precision to be effective in detecting spatial patterns of cutthroat trout abundance and may be a useful tool for providing the context for investigating fish-habitat relationships at multiple scales.

Publication type Article
Publication Subtype Journal Article
Title Evaluating single-pass catch as a tool for identifying spatial pattern in fish distribution
Series title Journal of Freshwater Ecology
DOI 10.1080/02705060.2005.9664974
Volume 20
Issue 2
Year Published 2005
Language English
Publisher Taylor & Francis
Contributing office(s) Forest and Rangeland Ecosystem Science Center, Northern Rocky Mountain Science Center
Description 11 p.
First page 335
Last page 345
Country United States
State Oregon
Other Geospatial Blowout Creek, Slide Creek
Online Only (Y/N) N
Additional Online Files (Y/N) N
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