Environmental DNA Sampling in the Lower Roanoke River

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The Roanoke River is considered one of the most important riverine systems for diadromous fish reproduction on the Atlantic seaboard. Beginning in 2016, the Corps revised flood operations at John H. Kerr Hydropower project to implement a more naturally variable flow regime, referred to as Quasi-Run-of-River (QRR). Under QRR, flood control releases mimic the natural inflows to the project to the extent possible while maintaining other project purposes. Intensive monitoring of diadromous fish recruitment has occurred on the Roanoke both pre and post QRR, yet limited work to date has connected observed population data for juvenile alosines (blueback herring, alewife, hickory shad) with river flow events. The Roanoke River is in the nationwide Sustainable Rivers Program as one of the original eight rivers from 2002. It is an ideal river to test new technologies to understand effects of water management decisions, and to relate this work to how it can be used nationwide. In this instance, the Corps is interested in using environmental DNA (eDNA) to understand the relationship between flows and the response from rare fish. This includes spatial and temporal variability to gather more information about where the juveniles are congregating, the condition of that habitat, and the flow regimes associated with the presence of the fish. The e-DNA technology will be assessed to understand if it is an appropriate tool to inform release decisions at Corps reservoirs. Brief Description of Anticipated Work: The objectives of this work are to: Test eDNA as a tool to study the relationships between river flows and fish species; Gather more data about flow effects on juvenile fish in the Roanoke River; Provide the Corps insight about the effect of reservoir releases on juvenile fish; Increase the knowledge of a critical missing element of fisheries knowledge Put the work in a broader context to consider ways the Corps can use eDNA technology in other rivers.

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