Reclamation Information Sharing Environment (RISE)

Early detection of dreissenid mussels (quagga and zebra) provides the ability to plan for and limit the impact these invasive bivalves. Proper preservation of field samples is critical to the success of early detection efforts, as it is necessary to maintain sample integrity to ensure the reliability of sample analyses. The current study evaluated the impact of five preservatives: 20% ethanol, 70% ethanol, 70% isopropanol, Longmire’s solution, and propylene glycol, on environmental DNA (eDNA) analyses for the detection of quagga mussel eDNA. All five preservatives successfully resulted in the detection of quagga mussel eDNA over 12-week time-course of the study. Results were further analyzed to calculate the starting quantity of target eDNA in the samples. 70% ethanol, 70% isopropanol, and propylene glycol all averaged similar starting quantities. Longmire’s solution resulted in lower average starting quantities. Samples preserved with 20% ethanol had much higher calculated starting quantities, which was unexpected and runs counter to conventional wisdom on the necessity for high alcohol concentrations to prevent eDNA degradation. The reasons for this anomalous result are uncertain, although they may relate to the specific design of the current study.