Genetic species identification in weatherfish and first molecular confirmation of Oriental Weatherfish Misgurnus anguillicaudatus (Cantor, 1842) in Central Europe

The Oriental Weatherfish is considered a globally invasive fish species. In Europe, several reported feral populations of Oriental Weatherfish display an overlapping distribution range with native weatherfish Misgurnus fossilis, a declining species of international conservation and aquatic management concern. Morphologically distinguishing the different weatherfish species can be difficult, as their coloration is highly variable, many species reveal high phenotypic plasticity, and morphological traits like coloration might be not obvious or might be degraded during field sampling and after preservation. Herein, we analysed suspicious weatherfish specimens from southern Germany, demonstrating the usefulness of molecular genetic species identifications in this genus. We present the first molecular genetic species record of Misgurnus anguillicaudatus in Central Europe, and confirm the range expansion of OrientalWeatherfish into the river Inn catchment in southern Germany. As accurate species identification is crucial both in the context ofmonitoring and conserving native endangered species, and in early detection and prevention of biological invasion, we suggest the standard use of genetic species identification if morphological traits are not obvious.