Acknowledgements
This study was financed by the Innovation Fund Denmark through the project “DNA-based species identification in bulk tissue samples for environmental monitoring” (grant number 1355-00144B) and Amphi Consult ApS. The authors wish to thank biologist Per Gørtz (Laboratory of Fish Ecology; Fiskeøkologisk Laboratorium, Helsingør, Denmark) for his help with sampling and analysing the water stream samples.