Meeting Abstract
The emergence of environmental DNA (eDNA) detection provides a powerful tool to detect and monitor biodiversity, including invasive species. The European green crab, Carcinus maenas, is an invasive species world-wide and monitoring its populations is important. To use eDNA, species-specific primers are required. We tested primers developed for C. maenas in Australia and published by Bott et al. (2010) on green crabs and other native species in the Gulf of Maine, USA. We found the primers to also detect H. sanguinaeus, C. irroratus, H. americanus, and other species. Therefore, new primers and probes were designed using the COI gene of C. maenas and tested on multiple native species, as well as green crabs from Newfoundland, Iceland, and Nova Scotia. These were found to be species specific and detect crabs from all 4 populations. We further investigated the dose dependent quantity of eDNA as well as the degradation rate to test whether the eDNA approach can be used to quantify the abundance of crabs in the environment. Crabs were incubated for 7 days in 4 gallons of aerated artificial seawater. Concentrations of eDNA of C. maenas under these conditions was dose-dependent. Degradation of varying amounts of eDNA in water samples showed detectability up to 2 days with a near logistic decay. Therefore, the identified absolute amounts of eDNA in a water sample is dependent on number of animals present and the timing of the collection of samples, making eDNA concentrations as a tool for quantification not usable. Our work shows that species specific eDNA primers need to be verified with the respective local species, and should not be used for quantification. Funded by NSF grant# IUSE-1431955 to M.F.
