Journal article
First record of the non-indigenous jellyfish Blackfordia virginica (Mayer, 1910) in the Baltic Sea
National Institute of Aquatic Resources, Technical University of Denmark1
Section for Oceans and Arctic, National Institute of Aquatic Resources, Technical University of Denmark2
Helmholtz Centre for Ocean Research Kiel3
Section for Marine Living Resources, National Institute of Aquatic Resources, Technical University of Denmark4
Kiel University5
Marine invasions are of increasing concern for biodiversity conservation worldwide. Gelatinous macrozooplankton contain members, which have become globally invasive, for example the ctenophore Mnemiopsis leidyi or the hydromedusae Blackfordia virginica. B. virginica is characterised by a large salinity tolerance, with a brackish-water habitat preference, and by a metagenic life history strategy with an alternation between sexually reproducing planktonic medusae and asexually reproducing benthic polyps to complete the life cycle.
In this study we analysed 8 years of ichthyoplankton survey data (2010-2017) from the Kiel Canal and 14 ichthyoplankton summer surveys in the central Baltic Sea (2008-2017). We report the first presence of B. virginica in northern Europe, namely from the southwestern Baltic Sea and the Kiel Canal. In the Kiel Canal, B. virginica was first sporadically sighted in 2014 and 2015 and has developed persistent populations since summer 2016.
Changes in size-frequency distributions during summer 2016 indicate active recruitment in the Kiel Canal at salinities between 7 and 13 and temperatures > 14 °C. Close vicinity to and direct connection with the southwestern Baltic Sea, where B. virginica was observed during 2017, indicate that the Baltic Sea and other brackish-water habitats of Northern Europe are at risk for colonisation of this non-indigenous species.
Our results highlight that monitoring activities should consider gelatinous macrozooplankton for standard assessments to allow for the detection of non-indigenous species at an early stage of their colonisation.
Language: | English |
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Year: | 2018 |
ISSN: | 14383888 and 1438387x |
Types: | Journal article |
DOI: | 10.1186/s10152-018-0513-7 |
ORCIDs: | Jaspers, Cornelia and Huwer, Bastian |