Brook trout (brkt) are a management priority for federal, state, and tribal agencies around lake superior (LS)

This Project Grant award from the U.S. Department of the Interior's Fish and Wildlife Service (under CFDA Program 15.608 - Fish and Wildlife Management Assistance) provides $329,464.74 to the University of Wisconsin System to study brook trout habitats and movements in Minnesota's Lake Superior tributary streams. The research aims to: 1) determine seasonal habitat use and movements of brook trout, brown trout, and steelhead trout; 2) assess habitat overlap and competition between native brook trout and non-native salmonid species; and 3) identify cold-water refuges for brook trout in the face of climate change. The project will be conducted in the Knife and Stewart River watersheds from 2024-2026, involving fish tagging, habitat monitoring, and collaboration with local conservation groups. Deliverables include a graduate student thesis, scientific publications, and recommendations to inform future fish management decisions in the Great Lakes region.

Conservation of this native, cold-water-dependent species is possible, but requires proper knowledge and management of their habitats. Warming and more variable climates and water levels are threatening brkt, and these effects are even more extreme in the great lakes region. Specifically, LS tributary streams in MN lack the cold, groundwater inputs that exist in many other areas making these streams more susceptible to climatic effects. Therefore, identifying and understanding the habitats brkt use and have available, and how trout move throughout these streams is important for trout management. In addition to threats from climate change, brkt in MN tributaries coexist other nonnative salmonids (trout and salmon species) that can survive warmer water temperatures. These nonnative salmonids represent important recreational fisheries and steelhead (rainbow) trout (SRT) are stocked by the MN department of natural resources (mndnr) to create and enhance fisheries. However, brkt can be outcompeted or have their habitat use altered by nonnative salmonids. Presently, we do not know a lot about the interactions among trout species in MNS LS tributary streams. Therefore, we are proposing to determine seasonal habitat availability and use, and movements of trout species in MNS tributary streams to LS. The research questions: what habitats do brkt use at different times of the year in streams with and without nonnative salmonids is there habitat overlap among brkt, brown trout (BT), and SRT where are cold-water refuges in these streams and do these habitats change seasonally or with water level how often are trout using restored habitats in the knife and stewart rivers what are movement patterns of trout in these streams and how do their movements relate to flow, temperature and habitat availability objectives: determine (1) seasonal movements, habitat use and relative abundance of brkt, BT and SRT, (2) if brkt habitat use differs between streams with and without nonnative salmonids,(3) if movements of salmonids are related to discharge, temperature and oxygen levels, and (4) where brkt thermal refugia exists seasonally within two northshore LS watersheds.work will be done in the knife and stewart rivers along LSS northshore during 2024-2026. Fish will be captured using electrofishing, and mndnr fish traps (knife river). Once captured, we can estimate the number, sizes, and ages of fish in the streams. We plan to implant about 2,500 total trout with passive integrated transponder tags (PIT)and about 60 trout with radio transmitters. Fish movements are determined using the PIT tag microchips by placing tag readers at strategic locations throughout the streams. When a PIT tagged fish swims past the tag reader the PIT number and the time the fish swam past is recorded. Habitat use can be determined using radio transmittered fish by tracking the location of these fish by listening for radio signals using a hand-held antenna. We will be assessing fish habitat including flow rates, water clarity, depth, temperature, and oxygen levels, and steam substrates and bank conditions. Water conditions and habitat will be compared between sites where fish are located and where we dont find fish to determine what habitats trout prefer. Deliverables: we plan to train a graduate student to earn their master of science, develop a project report, and publish results in scientific journals and conservation magazines. Results will be presented at scientific conferences and to local conservation groups. We are collaborating with local fishing and conservation organizations and the two harbors high school environmental club to teach students about conservation and help train future scientists. Results will guide future management decisions about fish passage and habitat improvements throughout the great lakes region.