Presence/absence of jellyfish species Blackfordia virginica in the Kiel Canal 2018-2022

We present presence/absence data for the invasive gelatinous plankton Blackfordia virginica in the Kiel Kanal for the years 2018 to 2022 . The sampling a site is Weiche Groß Nordsee at 54.342N, 9.961E. The sampling was perfomered within framework of the Kiel Fjord Ichthyoplantkton timeseries. Sampling through the entire watercolumn (down to 9 meters depth) was done from FB Polarfuchs using a Bongo net with 500 and 335 micron mesh towed at approx. 3kn speed. The catch of the 500 micron Bongo net was examined directly for the presence of Blackfordia virginica after the haul before being fixed in 4% bufferede formaledehyde solution. During later lab analysis the sample was again examind for the presence of the species. In addition we present accompanying salitnity and temperature measurements at 1 m depth.