Traditional methods for freshwater crayfish monitoring require bulky field equipment and are often time consuming. In recent years, this has led to an increased number of studies that rely on environmental DNA (eDNA) collection for detection of crayfish in water samples. Typically, these samples are collected thorough active filtration followed by DNA isolation and qPCR detection of the species. In HessenSentinel, we test a simplified passive eDNA sampling methodology to evaluate its suitability for detection of the endangered European noble crayfish (Astacus astacus) and invasive North American signal crayfish (Pacifastacus leniusculus) and invasive spiny cheek crayfish (Faxonius limosus).

Project aims:

The objective of HessenSentinel is to assess the distribution of noble crayfish, signal crayfish and spiny-cheek crayfish in the State of Hesse, and test the passive eDNA sampling as potential tool to serve as early warning system for detecting invasive species. In this context, passive eDNA sampling is planned at five major rivers in Hesse at three locations each: Main, Nidda, Lahn, Fulda and Rhine.

We deploy eDNA samplers at 13 locations (with 2-4 replicates) across the Federal State of Hessen (Germany). After 12-16 hours, the samplers containing different filter material are collected, DNA is isolated and samples are tested for the presence of crayfish species using established qPCR protocols.