Biomass of coastal cutthroat trout in unlogged and previously clearcut basins in the central Coast Range of Oregon

Transactions of the American Fisheries Society
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Abstract

Populations of coastal cutthroat trout Oncorhynchus clarki clarki were sampled in 16 Oregon headwater streams during 1991–1993. These streams were above upstream migration barriers and distributed among basins that had been logged 20–30 and 40–60 years ago and basins that had not been logged but had burned 125–150 years ago. The objective of our study was to characterize the populations and habitats of age-1 or older cutthroat trout within these three forest management types. Streams within unlogged basins had relatively low levels and a small range of trout biomass (g/m2). Streams in basins logged 40–60 years ago supported low levels but an intermediate range of trout biomass. Streams in basins logged 20–30 years ago supported the widest range of biomass, including the lowest and highest biomasses among all streams sampled. The variable that best explained the variation of trout biomass among all 16 streams was the amount of large woody debris (LWD). All streams were heavily shaded during at least part of the year by mostly closed tree canopies. Deciduous trees were more prominent in canopies over streams in logged basins, while conifers were more prominent in the stream canopies of unlogged basins. Our results suggest that trout production in basins extensively clear-cut 20–60 years ago may generally decrease or remain low over the next 50 or more years because of decreasing loads of remnant LWD, persistent low recruitment potential for new LWD, and persistent heavy shading by conifers. These logged basins are not likely to show an increase in trout biomass over the next 50 years unless reset by favorable natural disturbances or by habitat restoration efforts.

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Publication type Article
Publication Subtype Journal Article
Title Biomass of coastal cutthroat trout in unlogged and previously clearcut basins in the central Coast Range of Oregon
Series title Transactions of the American Fisheries Society
DOI 10.1577/1548-8659(1999)128<0890:BOCCTI>2.0.CO;2
Volume 128
Issue 5
Year Published 1999
Language English
Publisher American Fisheries Society
Contributing office(s) Western Fisheries Research Center
Description 10 p.
First page 890
Last page 899
Country United States
State Oregon
Other Geospatial Coast Range
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