The invasive comb jelly Mnemiopsis leidyi is a lobate ctenophore native of coastal and estuarine waters of the temperate western Atlantic Ocean. In the last decades this species has expanded its range of distribution, colonizing marine and transitional environments in Europe. In October 2015, during a survey fishing the European eel Anguilla anguilla in Sardinia (western Mediterranean), a massive bloom of this specie was obser...