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Diel Habitat Selection by Brown Trout in the Rio Grande River, Colorado, after Placement of Boulder Structures
Author(s) -
Shuler Scot W.,
Nehring R. Barry,
Fausch Kurt D.
Publication year - 1994
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(1994)014<0099:dhsbbt>2.3.co;2
Subject(s) - brown trout , salmo , juvenile , trout , diel vertical migration , habitat , fishery , fish <actinopterygii> , environmental science , geography , ecology , biology
Brown trout Salmo trutta distribution and microhabitat use were measured in 10 study sections of the Rio Grande River, Colorado, where three types of structures made from large boulders had previously been placed. On average, 65% of the adult brown trout and 69% of the juvenile brown trout observed were holding positions near structures. Brown trout used primarily wingdams, midchannel boulder clusters, and natural bank cover, and avoided single boulders and areas with no structures. Juvenile and adult brown trout showed a significant preference for wing‐dams during the day at both high and low flows, but adults shifted from wingdams to midchannel boulder clusters at night during low flows. Distributions of water depth and mean water velocity at positions used by brown trout differed significantly between age‐classes but were generally not significantly different at high versus low flows, between day and night, or between fish using and not using structures. Results suggest that brown trout selected feeding sites primarily based on water velocity and cover, and that boulder structures provided more locations that were energetically favorable for brown trout.