*WINNER* Development of an environmental DNA (eDNA) assay to delineate the distribution of the imperiled Striated Darter (Etheostoma striatulum, Page and Braasch 1977) in the Duck River, Tennessee

Abstract

Striated Darters (Etheostoma striatulum) are small, uncommon darters endemic to the Middle-to-Upper regions of the Duck River, Tennessee. Since their description, they have become increasingly rare within their range. Historically, Striated Darters occupied 16 tributaries of the Duck River; as of 2011, their known distribution has declined to nine tributaries. Due to this documented decline, Striated Darters are currently under review for federal listing under the Endangered Species Act. Effective management and conservation of this species will also require information about their distribution. This study aims to delineate the present-day distribution of the Striated Darter through a species-specific environmental DNA (eDNA) assay. Aquatic species discard DNA fragments in many ways (e.g., urination and reproduction) into the water column which can then be identified using well-established molecular techniques. Due to the Striated Darter's reclusive and cryptic behavior, conventional techniques are ineffective for detection, requiring the use of much more efficient and sensitive eDNA monitoring techniques. At 30 historical sites in the Duck River, three water samples will be taken and then filtered for molecular analyses. A qPCR assay will be designed to detect Striated Darters across all sites and conclusions will be run through a hierarchical occupancy model to test for the probability of detection at the qPCR replicate, sample replicate, and site levels. Another project investigating the population status of the Striated Darter will be running similar occupancy models using conventional techniques, which will allow for comparison between traditional and molecular approaches.