MONIS6 (‘Monitoring of non-indigenous species’ 6), Status of environmental DNA monitoring in marine areas under the NOVANA program for 2017 to 2023

The distribution of marine alien species is difficult to map using conventional monitoring. To gain a better understanding of where in Danish waters alien species occur and have their most frequent distribution, this project maps the detections of environmental DNA from alien species detectable in filtered water samples in the period 2017-2023.

Since 2017, the Danish Environmental Protection Agency has annually collected water samples from marine monitoring stations from both open sea and coastal areas in Denmark. All water samples are filtered during fieldwork and then emptied of water and stored frozen. NIVA Denmark, in collaboration with the Natural History Museum of Denmark, has analysed 300 water samples for environmental DNA from marine alien species using species-specific detection systems and quantitative polymerase chain reaction (qPCR) to assess the levels of the species' environmental DNA in the water samples. Although the levels of environmental DNA cannot be translated into biomass or number of individuals, it can give an indication of where alien species are found in Danish waters. Compared to other findings reported in databases, there is a tendency for an increase in findings and detections of alien species in the period 2017-2023.

In addition, the project presents five novel species-specific tracking systems that have the potential to help detect environmental DNA from alien species that have not previously been monitored in Danish waters.