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Environmental DNA Early Detection Monitoring Identifies an Advancing Round Goby Invasion Front
Citation:
Waits, E., M. Acre, L. Smith, D. Walters, AND M. Mills. Environmental DNA Early Detection Monitoring Identifies an Advancing Round Goby Invasion Front. American Fisheries Society, Grand Rapids, MI, August 20 - 24, 2023.
Impact/Purpose:
Early detection of invasive species via eDNA surveillance will allow environmental managers to consider remediation and eradication options at early stages of invasion.
Description:
Invasive species threaten the biodiversity, structure, and function of aquatic ecosystems. Once established, eradicating invasive species is an arduous task, imposing a significant financial burden on environmental management entities. Early detection of invasive species is crucial to successful remediation and eradication programs. Environmental DNA (eDNA) surveillance is a valuable tool that can be used to augment traditional invasive species monitoring programs and may enable higher spatial and temporal resolution during early stages of invasion when species are difficult to detect due to low population densities. Leveraging eDNA metabarcoding, we have detected an advancing invasion front of the round goby (Neogobius melanostomus) in the Cuyahoga River. The round goby is an aggressive bottom dweller that displaces native fish. The species invaded the Great Lakes in the early 1990s, was later detected in the Cuyahoga River in 2001 near the mouth at Lake Erie and has been advancing upstream since. By 2021, it was observed upstream from the former Station Road Dam at RM 20.7, which was thought to be a physical barrier for round goby migration upstream. Recently, in coordination with electrofishing surveys, we documented round goby eDNA further upstream in water samples collected during September 2022, indicating the invasion front is advancing at a rapid pace. Two independent metabarcoding assays targeting 12s and 16s mtDNA detected 2.1x104 and 3.2x103 copies of round goby eDNA/liter, respectively, at RM 24.1. At RM 26.6, approximately 26x fewer copies of round goby eDNA were detected, but none were detected at sites further upstream. Taken together, the reduced level of eDNA present at RM 26.6 is suggestive of lower population densities and that this site is close to the invasion front. We are presently monitoring upstream migration bi-monthly via eDNA surveillance. The current status of round goby invasion in the Cuyahoga River will be discussed.
