Monitoring marine alien species in Norway - A pilot study for implementing a national program

Abstract

In this pilot study we tested the efficiency of different methods to detect alien marine species in three different ports in Rogaland County. The methods used followed by far the recommendations in the HELCOM protocol, which is developed for the Baltic Sea, but also included beach survey, video survey, dredging and extensive use of DNA-methods. Material from zooplankton samples, scrapings from settlement panels as well as e-DNA samples from filtrated water and sediments were subject to meta-barcoding. A total of 33 alien species were recorded in this study, of which seven were door knockers to the Norwegian coast. The conventional methods recorded 19 alien species, and the methods RCS in marinas, settlement panels and beach surveys had the highest detection rate. DNA-methods detected 26 alien species, and scrapings from settlement panels and water samples were the most efficient methods. We recommend a combination of conventional and DNA-methods to be used in a national monitoring program. Although sampling of mobile fauna yielded no alien species in the pilot area we still recommend to use this method, being the best method for catching alien crabs and fishes.

Monitoring marine alien species in Norway - A pilot study for implementing a national program