High‐volume plankton tow net sampling improves eDNA detection of invasive zebra mussels (Dreissena polymorpha) in recently infested lakes

• Published in: Environmental DNA (Hoboken, N.J.) Vol. 6; no. 2
• Main Authors: L Miller, Dulaney, Amish, Stephen, Howard, Leif, Bajno, Robert, McCartney, Michael, Luikart, Gordon
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley & Sons, Inc 01-03-2024; Wiley
• Subjects: Biodiversity; Dreissena; Dreissena polymorpha; early detection; eDNA; Environmental DNA; Environmental economics; Filtration; Freshwater ecology; high‐volume sampling; Indigenous species; Introduced species; Invasive species; Juveniles; Lakes; Larvae; Mollusks; Monitoring; Mussels; Nonnative species; non‐native species; PCR sensitivity; Plankton; plankton tow net; Polymerase chain reaction; Pore size; Sensitivity; Shellfish; Water analysis; Water purification; Water sampling; Lake Winnipeg; Canada; Manitoba Canada; United States > US; Minnesota; Columbia River; North America
• ISSN: 2637-4943; 2637-4943
• DOI: 10.1002/edn3.511

Aquatic invasive species are a serious and growing threat to biodiversity. Zebra and quagga mussels (Dreissena polymorpha and D. rostriformis bugensis) are freshwater invaders causing substantial ecological and economic damage across Europe and North America. Early detection of invasive mussels and other non‐indigenous species is increasingly needed to prevent their establishment and spread. Environmental DNA (eDNA) techniques potentially offer higher sensitivity monitoring tools to complement more conventional methods for surveying adult and juvenile mussels and veliger larvae. eDNA assays are typically performed on small‐volume (0.5–5 L) water samples that are concentrated by filtration prior to extraction and downstream processing. Sampling using a towed plankton net of a larger (64 μm) pore size can process orders of magnitude larger water volumes with the potential for increasing eDNA detection sensitivity. We compared the sensitivities of high‐volume plankton tow net water sampling to filter sampling in three recently infested lakes in Canada and Minnesota, USA. Paired filtration and tow net samples were analyzed for Dreissena DNA using an established quantitative polymerase chain reaction assay for the genus. Higher yields of Dreissena eDNA (more DNA copies) were recovered from plankton tow than from filtered samples in all 33 paired comparisons. In some cases, plankton tow samples were positive for Dreissena eDNA while lower‐volume filtering produced a false negative detection. Our results demonstrate the effectiveness of plankton tow net sampling for eDNA early detection of invasive mussels, a method that can be used exclusively or as a supplement to filter sampling. Our results further suggest that eDNA testing could be incorporated into monitoring programs that routinely use plankton tows for visual detection of invasive mollusk larvae, as well as other aquatic invasive and non‐invasive species ranging from plankton to metazoans, including many fish.
Environmental DNA (eDNA) techniques offer sensitive monitoring tools for the early detection of aquatic invasive species, which is increasingly needed to prevent their establishment and spread. We compared the eDNA sensitivities of high‐volume plankton tow net water sampling to conventional low‐volume water filtration methods in three lakes of known recent zebra mussel (Dreissena polymorpha) infestations. Paired filtration and tow net samples were analyzed for Dreissena DNA where higher yields of Dreissena eDNA (more DNA copies) were recovered from plankton tow than from filtered samples in all 33 paired comparisons.