DNA barcoding library for detection of target non-indigenous species gets new data

October 2020

Correct identification of target species, i. e. species, which “may impair or damage the environment, human health, property or resources and are defined for a specific port, State or biogeographic region” (IMO, 2007. Guidelines for Risk Assessment Under Regulation A-4 of the BWM Convention) is of critical importance for the management of biological invasions, resulting both from ships’ ballast water and biofouling. Traditional species identification methods that are based on the morphology of organisms can be time consuming and require taxonomic expertise which is often lacking, moreover such methods may fail to identify species at early life stages. That’s why the COMPLETE project focused on the further development of molecular methods that allow quick and accurate identification of target species at any stage of life.

The project partners have developed a procedure for selecting the species for which a molecular library is to be created. The preliminary list was taken from AquaNIS, an information system that stores information on biological characteristics, ecological limits and movements of non-native aquatic species. The selected species were those that are currently spreading in the Baltic Sea, are potential target species (according to IMO definition) and do not yet have a molecular barcode. For that purpose, all preliminary listed species were screened in various global gene databases to find out if there are molecular markers for them.

Samples of the selected species were collected according to a standardized protocol by project partners in Poland (University of Gdansk, UG), Finland (Finnish Environment Institute, SYKE), Estonia (University of Tartu, UTARTU) and Lithuania (University of Klaipeda, KU). The sampling protocol included: sampling guidelines (sampling in the field, species identification, sample photograph, long-term sample storage, labeling) and sample identifier (species name, sample size, data and location of sample collection, accurate GPS coordinates of sampling site sampling, information about the collector, environmental data of the sampling site, sampling method, taxonomist name, contact person). In addition, samples of native organisms that were morphologically close to the selected species were used for molecular analysis.

Further work was performed in the Environmental genetics laboratory of the Marine Research Institute (KU). In total 73 bar-codes were established for six alien and three native species. Metadata on the availability of molecular information for the selected species was entered into AquaNIS with corresponding registration numbers in GenBank, a global genetic sequence database that compiles all publicly available DNA sequences. These data will be used for the early detection of new introductions, as well as for tracking the spread and population dynamics of already established invasive species. It is useful for work with environmental samples taken from ballast water, biofouling, ballast tank sediments as well as ambient water and sediments, where eDNA can be extracted directly without the need to capture target organisms.

The bivalve mollusk, wedge clam Rangia cuneata and a mud crab Rhithropanopeus harrisii, now spreading in the Baltic Sea and their GenBank vouchers (photo: Sergej Olenin)