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    Humphrey, Olivia, Clean Water Institute, Lycoming College, 1 College Place, Williamsport, PA, 17701,; Kaunert, Matt, Clean Water Institute, Lycoming College, 1 College Place, Williamsport, PA, 17701,; Rieck, Leslie, Clean Water Institute Lycoming College 1 College Place Williamsport PA, 17701,

    Pennsylvania has ~83,000 miles of streams (~62,725 streams) that face a variety of anthropogenic stressors when left without legal protection. Native trout populations are at risk of decline and local extirpation due to factors such as land use change, resource extraction, and road construction. Waterways designated as wild trout streams are afforded protections from human-induced impacts. In 2010, the PA Fish and Boat Commission (PFBC) began the Unassessed Waters Initiative (UAI), a collaborative statewide effort to “Proactively identify and properly classify the most at-risk streams which support naturally reproducing trout populations in order to protect, conserve and enhance those waters as wild trout streams.” Lycoming College Clean Water Institute (CWI) has been involved with UAI for over a decade, contributing annual surveys of unassessed stream reaches. Here, we provide an update on CWI’s contribution to the Unassessed Waters Initiative from 2012-2023. We sampled fish populations following PFBC protocols, consisting of single-pass electrofishing surveys (100-300 meters per reach) using a Smith-Root electrofishing backpack. We identified all captured fish, and measured body length and abundance of trout species. We recorded reach length and width as well as water chemistry variables (temperature, DO, pH, alkalinity, conductivity) at each site. We evaluated effects of DO and reach width on trout abundance using generalized linear models with a Poisson distribution. From 2012-2023, CWI surveyed 657 stream reaches in cooperation with UAI, in which 275 (42%) were occupied by wild trout populations. In 2023, we surveyed 40 stream reaches in Lycoming, Tioga, Clinton, Centre, and Potter counties, documenting 12 new wild trout populations (9 brook trout, 3 brown trout), 2 reaches with no fish present, and 14 dry reaches. We found a significant positive effect of DO on trout abundance (z = 14.15, df = 253, p < 0.001), with highest abundances > 8 mg/L. We found a significant positive effect of stream width on trout abundance (z = 3.093, df = 272, p <0.01), with highest abundances in streams between 1-5 m wide. Statewide, ~35,000 streams have not yet been assessed, many of which are small 1st – 2nd order streams potentially supporting wild trout populations. CWI will continue its partnership with PFBC contributing to the identification and protection of wild trout waters throughout Pennsylvania. We will also explore the potential for environmental DNA (eDNA) sampling to compliment electrofishing surveys and improve trout detection rates across Pennsylvania.

    trout, Unassessed Waters, PA Fish and Boat