Wisconsin Fishery Project
Genetic assessment of Boardman River fish populations prior to dam removal
September 2018 - August 2020
- Great Lakes Fishery Commission
Fragmentation caused by dams can fundamentally alter population structure and genetic diversity of fish species that once had access to a continuous river system. Providing fish passage has potential to remedy these impacts, but few studies have directly quantified the effectiveness of fish passage for restoring genetic connectivity and increasing genetic diversity. The FishPass project on the Boardman River represents a unique opportunity to investigate this topic. Fish populations above the Union Street Dam have been isolated from Traverse Bay since the dam’s construction in 1867. The FishPass project will restore connectivity between the Boardman River and Traverse Bay, allowing species such as walleye, smallmouth bass, yellow perch, white sucker, and rock bass to access the upper reaches of the river. Collecting baseline genetic data from these species as well as eDNA water samples from sites above and below the dam will allow us to determine the genetic impact of fish passage on fish populations above the dam and investigate distribution patterns of species that are being passed. We hypothesize that decreases in genetic differentiation between populations above and below the dam and increases in genetic diversity of above dam populations will be detectable 5-10 years after fish passage has been initiated. However, it is likely that these effects will vary substantially by species due to differences in life history. We also hypothesize that eDNA will represent a useful tool for monitoring species diversity and distribution patterns.