Not a Silent Invasion: The Reaction of European Naturalists to the Spread of Zebra Mussel (Dreissena polymorpha) in the 19th—Early 20th Century

The case of naturalization of the zebra mussel, Dreissena polymorpha (Pallas), in coun-tries lying beyond its native Ponto-Caspian range is remarkable as one of the first instances, when the scientific community as early as the mid-19th century was fully aware of the non-indigenous status of a particular species as well as of the need for the study and monitoring of this process. Based on a study of contemporary sources, I reconstruct the early response of the European naturalists (including those that today would be called ‘citizen scientist’) to the invasion of Dreissena and describe their attitudes to the problem, including the divergence of opinion about the origin and the means of dispersal of this bivalve species. An analysis of pa-pers of the English, French, German, and Russian authors published between 1774 and 1920 has shown that the invasion of D. polymorpha was by no means ‘silent’; quite opposite, it provoked an immediate reaction of naturalists, and the scientific agenda for the study of the new invader was proposed in England as early as 1838