First European ring test to detect crayfish eDNA.

This present study was initiated during a two-day workshop on eDNA methodology in February 2020, at the Institute of Freshwater Research, Swedish University of Agricultural Sciences (SLU), Stockholm. The workshop had 28 participants from nine countries (Sweden, Croatia, Denmark, Estonia, Finland, Germany, Norway, Spain, and Switzerland). The ring test itself was delayed due to covid-19 pandemics. It was conducted on May 24, 2023, at the Institute of Freshwater Research, SLU. The experiment involved 11 research teams comprising 26 participants from 13 European countries (Sweden, Croatia, Czechia, Estonia, Finland, France, Germany, Ireland, Norway, Switzerland, Slovenia, Spain, and the UK). Each team brought and operated their own eDNA sampling equipment (including filtration pumps, hoses and filters) and followed their own protocols from eDNA isolation to qPCR amplification and analysis.