Autecology of Salmo trutta: Part II. Effects of current fluctuations on the position of Salmo trutta in a Michigan stream.

Abstract

The changes in positions held by brown trout (Salmo trutta) in a stream environment when subjected to changing current was studied in a stretch of Carp Creek, Cheboygan Co., Mi. Four brown trout were observed in a caged area for approximately fifteen minutes each. Cover, substrate, position in water column and location on the established grid system were noted; current and depth measurements were taken after the observation period at those points. Observations were taken with natural current flow and with the current diverted from the experimental area by an upstream dam. Brown trout did not appreciably change in behavior or position with different current velocities; cover and pools were preferred in both situations. Under the range of conditions of the experiment, no significant behavioral adaptations were discernible in the brown trout.