Michigan Department of Conservation
Research and Development Report No. 23
Institute for Fisheries Research Report No. 1703, 1965
Observations on the Natural History of Rainbow Trout
and Rainbow Trout Fishing in the East Branch of
the Au Gres River, Iosco County, Michigan
David S. Shetter
Introduction.-Michigan anglers and the
Michigan Department of Conservation have more than a passing interest in the rainbow
trout (Salmo gairdneri) of the East Branch of the Au Gres River. This stream
system is relatively close to southeastern Michigan population centers, and receives
considerable angling pressure.
Since 1942 the Conservation Department’s Fish Division has been involved in various investigations on this stream. Scale samples, measurements, and other life history data were collected from rainbow trout in the course of these investigations. The purpose of this paper is to consolidate the more pertinent findings in order to present a useful picture of the age and growth of these lake-run rainbow trout, and to discuss briefly some of the observations made on the East Branch of the Au Gres River during the past two decades.
Angling results on various parts of the drainage are described in several earlier Institute for Fisheries Research reports (639, 734, 950, 1016, 1050, 1131, 1274, 1396, 1439, 1483).