Michigan Department of Natural Resources
Fisheries Research Report No.1815, 1974
Transfer Releases of Coho Salmon and Trout into an Upper Part of Platte River, and
Observations on Salmonid Spawning
Clarence M. Taube
Abstract.-Adult coho salmon (600 males and 600 females) were introduced into a 1.4-mile stretch of Platte River (above the State hatchery) each fall in 1969, 1970, and 1971, to provide populations of young coho for a study of competition between salmon and trout. The total read count in the respective years was 311, 357, and 262; and success of reproduction was rated moderate, poor, and poorer, respectively. Many eggs were retained by the salmon to the time they died; retention was estimated at approximately 44, 51, and 67% in the respective years. Possibly a relationship existed between the high rate of retention and the considerable mortality of eggs and fry that has occurred in the hatchery. All of the rainbow trout and brown trout that entered the weir, along with coho salmon, were passed upstream also. Observations were made on spawning behavior of the three species. Spawning habits of rainbow trout and coho were similar in several respects, while the habits of brown trout were different from both. Number of reads per 300 lineal feet of stream, by species and stream section, during 1969-71, ranged as follows: rainbow trout,, Exp.. Sect. I, 4 to 6 reads; coho salmon, Exp.. Sect. I, 13 to 15 reads; and brown trout, Control Sect., 1 to 2 redds.