The upper black river has long been considered one of northern michigans most pristine brook trout streams.however, in-stream barriers, most notably from road crossings, have historically limited…

This Cooperative Agreement award from the U.S. Fish and Wildlife Service under the National Fish Passage Program (CFDA 15.685) provides $122,108 to Miami University to investigate how river fragmentation impacts the genetic diversity and gene flow of brook trout populations in the Upper Black River watershed in Michigan. The project will compare genetic variation in brook trout populations between stream segments with and without restored connectivity due to previous culvert replacement efforts. The research will collect tissue samples from up to 600 trout across 20 sites and sequence them to analyze genetic diversity and migration patterns. The results will inform the agency on how replacing culverts with bridge crossings improves genetic connectivity for this sensitive brook trout population. The award period is from July 1, 2024 to December 31, 2026.

The upper black river has long been considered one of northern michigans most pristine brook trout streams.however, in-stream barriers, most notably from road crossings, have historically limited the movement of brooktrout throughout the watershed. Previous fwcos fish passage program has helped fund the replacement of overtwenty crossings within the upper black river. Our objective is to investigate how river fragmentation altersgene flow and genetic diversity of brook trout populations within the upper black river watershed and whethergene flow and genetic diversity are improved by RE-establishing connectivity within a stream. We will comparewithin- and among-population variation and levels and directionality of gene flow between streams withundersized underperforming culverts and streams where crossing have been restored. We will select 10 sites whereprevious restoration efforts have occurred and 10 sites that currently are suspected to be barriers of fishpassage. At each locality, we will collect tissues from up to 30 trout for a total of 600 individuals. Thesamples will be sequenced using double digest restriction-site associated DNA sequencing which allows forgeneration of tens of thousands of single nucleotide polymorphism markers. We will calculate within-populationgenetic variation statistics for each locality, and separately for fish up or down the stream from the potentialbarrier. These statistics, will provide an overview of the genetic variation within each locality. Amongpopulationgenetic variation statistics will show how populations are genetically similar to each other and whatis the relative gene flow and migration directionality. This project will inform the agency on how replacement ofculverts with bridge crossings improves genetic diversity and connectivity of brook trout populations.