Development of species-specific eDNA-based test systems for monitoring of non-indigenous Decapoda in Danish marine waters

Summary

We report the development of seven eDNA-based species-specific test systems for monitoring of marine Decapoda in Danish marine waters. The seven species are 1) Callinectes sapidus (blå svømmekrabbe), 2) Eriocheir sinensis (kinesisk uldhåndskrabbe), 3) Hemigrapsus sanguineus (stribet klippekrabbe), 4) Hemigrapsus takanoi (pensel-klippekrabbe), 5) Homarus americanus (amerikansk hummer), 6) Paralithodes camtschaticus (Kamchatka-krabbe) and 7) Rhithropanopeus harrisii (østamerikansk brakvandskrabbe). The following three are new developments: Callinectes sapidus, Hemigrapsus sanguineus and Hemigrapsus takanoi, whilst the remaining four previously developed under earlier phases of the MONIS projects have been tested again. The additional tests on the four previously developed assays were performed with a broader diversity of Decapoda known from Danish seas, to re-evaluate the specificity of these assays. This additional testing revealed that two previously published assays were unspecific, and to accommodate this, two new assays are presented replacing those previously published. We recommend that the species-specific eDNA assays presented here will allow for continuous monitoring of these species as part of the NOVANA monitoring programme.