Survival to Emigration of Stocked and Wild Steelhead in a Minnesota Tributary to Lake Superior
Fisheries and Aquatic Sciences Bryson Kautz (Not Pictured)
Steelhead Oncorhynchus mykiss are a naturalized sportfish in Lake Superior and its tributaries, and their population is primarily supported by natural reproduction. However, recent declines in abundance have prompted increased stocking efforts to supplement area fisheries. It is important for managers to understand how in-stream survival and emigration patterns of stocked steelhead compare to their wild counterparts to improve success of stocking. Survival to emigration and emigration patterns refer to in-stream survival of juvenile steelhead. Therefore, the objectives of our research were to determine (1) survival to emigration of stocked steelhead, and (2) whether stocking location, stream temperature, and flow rates were related to emigration rates and timing of both wild and stocked steelhead in the Knife River, Minnesota. In May of 2024, age-1 adipose clipped steelhead were stocked at two separate locations of the Knife River. Additionally, PIT tags were implanted in 10% of total stocked steelhead. Emigrating steelhead were sampled using the Knife River Anadromous Fish Trap. Only 568 of the 9,683 stocked steelhead survived to emigrate, suggesting relatively low survival of stocked fish. Emigration rates peaked in mid-June for both stocked and wild steelhead and were more correlated to increasing water temperatures in early summer than increased flow levels during this period. Our results suggest that steelhead stocked at age-1 had relatively low survival to emigration, but that the stocked fish behaved similarly to wild fish. This information will help provide insight for managers and possible changes to future stocking programs strategies for North Shore tributary streams.
Advisors: Justin VanDeHey, Ph.D. Dylan Undlin, B.S. Nick Peterson, M.S.
Subject Area: Fisheries and Water
Type: Poster
89
UW-Stevens Point College of Natural Resources
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