NIVA Denmark has together with the National History Museum at University of Copenhagen, DTU Aqua, NIRAS A/S and Litehauz ApS carried out the first ever nation-wide study of the occurrence of non-indigenous species in Danish harbours. The study was funded via the Danish Fisheries Agency’s FISK & HAV programme and carried out in close dialogue with the Danish Environmental Protection Agency.

The sampling was carried out using both conventional and biomolecular methods (eDNA). In total, 16 harbours were covered – Esbjerg and Aarhus, the two largest harbours in Denmark, with intensive sampling and 14 harbours with a reduced programme. 26 non-indigenous species were recorded using conventional sampling and 13 species were recorded using eDNA-based methods. Excluding overlapping records, we have recorded a total of 34 non-indigenous species in the 16 harbours studied. Based on the results, we conclude the following: 1) more non-indigenous species are found in the western parts of Denmark (North Sea region) then in the eastern parts (Baltic Sea), and 2) a few species previously unseen in Danish marine waters were recorded, i.e. the two bristle worms Eteone heteropoda (fam. Phyllodocidae) and Streblospio benedicti (fam. Spionidae). Further, we provide a proof-of-concept regarding the overarching objectives of the MONIS-project and the eDNA-based test systems developed. The results constitute a baseline for future studies in Danish ports and other hotspot areas and has been used in the NISAR-Project.

For information about the eDNA competences at NIVA Denmark, please contact dr. Steen W. Knudsen.

For information about the MONIS and NISAR projects, please contact dr. Jesper H. Andersen.