Business trip report, Poland, Koubová a Kouba

From 11 to 13 August 2025, we (Anna Koubová and Antonín Kouba) undertook a business trip to Poland. The aim was to investigate the distribution of the spiny-cheek crayfish (Faxonius limosus) in the vicinity of the village of Barnówko. This is the location where, in 1890, the German breeder Max von dem Borne released approximately 100 specimens of spiny-cheek crayfish originating from the Delaware River basin in Pennsylvania, USA.

 The original motivation for this introduction was to find a replacement for the disappearing populations of the native noble crayfish (Astacus astacus), which at the time was experiencing a mass die-off caused by what was then an unknown disease – crayfish plague. Due to its small size, the spiny-cheek crayfish proved unsuitable for fisheries or aquaculture purposes. However, it spread via the local Myśla River into the Oder and beyond – largely aided by human activity – eventually reaching almost all of Poland. Today, it can be found in more than twenty European countries and often remains a carrier of a specific and highly virulent genotype of the crayfish plague pathogen.

 Previous genetic studies conducted across Europe have shown low genetic diversity within spiny-cheek crayfish populations, a result of the relatively small number of individuals initially introduced. However, these studies have never included the area of its first release in Europe. Addressing this gap is the main focus of our current research.

 We would like to thank Maciej Bonk from the Institute of Nature Conservation of the Polish Academy of Sciences for his assistance with this project.