The zebra mussel (Dreissena polymorpha) is an invasive species that has spread to Swedish waters through boat traffic and has established itself in several lakes. Once the species gains a foothold, it can negatively impact the ecosystem by altering water quality and bottom structure, outcompeting native species, and causing damage to infrastructure, such as clogging water pipes. On behalf of the County Administrative Board of Skåne, an eDNA survey was conducted at 17 locations to map the species’ distribution and identify potential risk areas.
The survey confirmed the presence of zebra mussels in the Saxtorp Lakes, where the species had previously been identified, while no detections were made in other water bodies. All samples from the Saxtorp Lakes tested positive, confirming the reliability of the eDNA method and indicating large mussel populations in these areas. The absence of detections in other surveyed locations strengthens the conclusion that, at the time of the study, the zebra mussel had not yet established itself in other lakes within the study area.
The results demonstrate that eDNA is an effective and highly sensitive method for monitoring invasive species, enabling early detection and preventive measures before the spread escalates. This study provides an important foundation for future monitoring programs, where regular eDNA analyses can help track the species’ expansion and support targeted actions to protect local ecosystems and water infrastructure.
