Observations on Movements of Wild Trout in Two Michigan Stream Drainages

This report deals with the migration of wild brook trout and brown trout, over 7 inches long, in Hunt Creek and the upper Au Sable River system. Between 1934 and 1967 we jaw-tagged 3,320 brook trout and 5,615 brown trout; anglers recaptured and reported 346 of the brook trout and 480 brown trout. Brook trout were recaptured close to where they had been tagged and released--88% within 1 mile, the remainder within 11 miles. Migration of brown trout (in the Au Sable system) was more variable. Seven- to 13-inch brown trout remained (56–85%) within 1 mile of tagging sites. Many browns over 13 inches in the North and South Branches Au Sable migrated several miles (some up to 10 to 40 miles), but in the Main Au Sable 90% of the big browns were less than 1 mile from tagging site. Spring-tagged trout produced twice as many returns as did fall-tagged fish. Brook trout recoveries were 97% within the first year after tagging; 67% of the browns came within the first year; the other 33%, in 2 to 5 years.