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Comparison of Habitat Composition and Cutthroat Trout Abundance at Two Flows in Small Mountain Streams
Author(s) -
Herger Lillian G.,
Hubert Wayne A.,
Young Michael K.
Publication year - 1996
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1996)016<0294:cohcac>2.3.co;2
Subject(s) - trout , habitat , abundance (ecology) , streams , oncorhynchus , environmental science , biomass (ecology) , ecology , fishery , streamflow , channel (broadcasting) , relative species abundance , biology , fish <actinopterygii> , geography , drainage basin , computer network , cartography , engineering , computer science , electrical engineering
We assessed habitat features measured in the recently developed basinwide habitat inventory for their relations to abundance of native cutthroat trout Oncorhynchus clarki in small streams of the Rocky Mountains. We also evaluated the manner in which habitat and fish abundance changed as streamflow declined during the summer sampling season. Our observations corroborated the assumption that the basinwide habitat inventory is a valid technique for identifying channel unit types with differing levels of use by cutthroat trout. We found higher biomass of cutthroat trout in pools than in glides or riffles. Plunge pools had higher biomass than dammed pools. Biomass was greater in low‐gradient riffles than in rapids, and no fish were found in cascades. We observed an increase in the abundance of channel unit types, changes in the physical dimensions of channel unit types, and a decrease in overall stream length with declines in flow. We concluded that the basinwide habitat inventory does identify habitat features affecting the abundance of cutthroat trout, but variation in flow during summer changes the relative abundance and physical features of habitat units. Comparisons of basinwide inventories among years within a specific watershed may be affected by differences in discharge, so inventories should be conducted at similar discharges to enable meaningful assessment of possible changes in habitat.