Performance of Steelhead Smolts Stocked in Southern Michigan Warmwater Rivers

摘要

We evaluated post-stocking survival, returns, homing, and contributions ofsteelhead smolts of two strains stocked in three southern Michigan warmwater rivers. Post-stocking survival was examined by comparing abundance among various stocking groups in the summer Lake Michigan sport catch during 1988-93. Minimum estimates of river returns were obtained by creel census below the first dam (and by counts at one fish ladder) during 1988-94. For Little Manistee steelhead, post-stocking survival varied among years and decreased as stocking sites moved further upriver. About 50% of mortality on downstream-migrating smolts occurred in the final 8-16 km of the journey. Post-stocking survival was very high for Skamania steelhead stocked in the lower St. Joseph River, but much lower for those stocked upriver in Indiana. Minimum returns to Berrien Springs dam on the St. Joseph River averaged 15-16% for both strains but only 2-3% for Skamania fish stocked in Indiana. Homing of Little Manistee steelhead was strong, both to and within the river. On the average, 77% of adult steelhead recovered at a stocking location within the Grand River had been stocked at the site.