A recent paper by Florian Lüskow  &  Steen Wilhelm Knudsen investigates the population genetic on the marine invasive ctenophore ‘Mnemiopsis leidyi’, also known as the ‘warty comb jelly’ (dræbergoplen på dansk) in temperate Northern European seas. This ctenophore is native to the Atlantic coast of America but has over the past two decades spread across all inner Danish seas. It is now extremely common in every harbor in Denmark when we reach August.

Whether this introduced ctenophore has an ecological impact on the Danish native marine species is still unknown. It has been speculated that they could perhaps be feeding on the larvae and juveniles of Danish commercially important species such as herring, cod and flatfish.

The population genetic study found that there is no genetic variation in this ctenophore across the inner Danish seas. This suggests that it is the same population that is spread across all the inner Danish seas and also points towards a single first introduction that afterwards have been the original source for the introduction in Danish seas. 

This publication was completed with support from OBAMA-NEXT.

The full article is available at https://link.springer.com/article/10.1007/s10530-025-03531-6#Abs1.