Nuisance species in lake constance revealed through eDNA.
Biological invasions are a global threat to biodiversity especially for aquatic resources. The distribution of alien species is associated with human activities; therefore, exotic species tend to accumulate near big urban areas through different invasion vectors such as ballast water, hull fouling, aquarium and pet releases. The Rhine River region is one of the most economically important in Europe. Around 60 million people live in the river basin that is connected with other large European rivers via the Rhine-Main-Danube shipping canal. The Alpine Rhine flows to Lake Constance, which is the second largest subalpine lake in Europe. Here, eDNA metabarcoding was employed to inventory aquatic species from water samples in six riverine and four lake localities within Lake Constance region. A 313 bp fragment within cytochrome c oxidase subunit I gene was PCR amplified using generalist primers for metazoan and sequenced with MiSeq High-Throughput Sequencing platform. Seven invertebrate invasive species and the invasive fish Oncorhynchus mykiss were detected from eDNA. Species-specific primers were employed to confirm metabarcoded species. Most of the invasive species detected in this study correspond to samples from areas around lake ports, followed by other lake and degraded downstream river areas. Samples taken upstream of Lake Constance were free of invertebrate aliens. To establish common regulation and management actions regarding aquatic invasions in the three countries that share Lake Constance is recommended.