Year Established: 2013 Start Date: 2013-03-01 End Date: 2015-02-28
Total Federal Funds: $21,851 Total Non-Federal Funds: $113,241
Principal Investigators: Brady Porter
Abstract: Conservation management and planning of imperiled fish species is often challenging because of the difficulty to obtain accurate survey data using traditional sampling methods. Traditional sampling and monitoring efforts like electroshocking, benthic trawling and seining, may simply not detect species in low number because of diverse deep-water habitats, the need for large amounts of sampling effort, and the uncertainty inherently associated with sampling a species in low number [1,2]. Our five target species (bluebreast darter, spotted darter, Tippecanoe darter, gilt darter and river darter) inhabit large river systems and benthic trawling for benthic fish in large rivers can be challenging because it is labor intensive and often harms fish by abrasion with rocks and debris entering the trawl. In this study we propose to develop and refine environmental DNA sampling (eDNA) for monitoring the current range expansion of five imperiled darter species of the upper Ohio River system to overcome sampling difficulties in large riverine habitats. eDNA sampling from benthic water samples has the potential to be a rapid and less invasive technique to detect the presence of these state imperiled darter species. Further benefits include accurate target species identification, enhanced species detection sensitivity, and an overall reduction in sampling costs . Darters, which are small-bodied benthic fish, are considered indicator species of habitat integrity. Recent work has shown that small resident fish such as darters are great indicator species and should be incorporated into models that predict the effects of urbanization (increased storm run-off and impervious surfaces) , and the U.S. Environmental Protection Agency determined darters are indicator species for bioaccumulation of chemicals that are harmful to humans and biota . As potential prey for sport fish, darters are linked to Pennsylvania’s recreational fishery, which has an estimated worth between two and four billion dollars per annum . Another concern to imperiled darter species results from the seventeen navigational lock and dams (L/D) and yearly dredging which disturbs benthic habitat and causes fragmentation. Since 2004, the upper Ohio and lower Allegheny Rivers have had over fifteen million tons of substrate removed for commercial aggregates , and since the 1800s it’s been estimated that over one-half billion tons of substrate have been removed. Thus, imperiled species detection in the upper Ohio River system has implications for future dredging permits and surveys must be conducted before new localities are dredged. Darter populations in the upper Ohio River system are disjunct because of previous water quality degradation, the navigational lock and dam system and ongoing dredging activities. Therefore, these imperiled darter species appear to exist within suboptimal fragmented habitats as metapopulations (i.e. many large and small spatially isolated subpopulations). Despite this, all five imperiled darter species appear to have expanded their range over the past decade. We will use microsatellite DNA analyses on confirmed samples to determine the genetic population structure, genetic variation and metapopulation dynamics of the imperiled species to prioritize conservation management efforts. Ultimately, understanding metapopulation structure and dynamics will facilitate management strategies that prioritize conservation efforts toward genetically diverse source populations compared to smaller, genetically depauperate and ephemeral sink populations. This study will: 1) develop and validate eDNA sampling to monitor imperiled darter species as an accurate, non-invasive technique that will save time, labor, and reduce sampling costs and 2) monitor the expansion of imperiled darter species below eight L/D installations located on the Ohio, Beaver, Allegheny, and Monongahela Rivers and identify critical riverine and spawning habitat.