Fig. 1

Map highlighting Gyrodactylus salaris-positive states (medium-grey colouration). For territories such as France, Italy, Spain and Portugal only the status of the mainland is considered and larger islands (e.g. Balearic, Canary, Corsica, Sardinia, Sicily, etc.) under their respective sovereignty are considered as separate geographic entities. For the purposes of this study, Kaliningrad, the Russian exclave, is considered as a separate geographic zone to the main Russian state. The reports of G. salaris from Kazakhstan (or Tajikistan), France, Lithuania, Portugal, Slovakia and Spain (light-grey colouration) are questionable and need further verifications regarding the presence or absence of G. salaris. The Republic of Ireland and the UK (including Northern Ireland) are the only two countries currently declared G. salaris-free, as are the water catchments of the Tenojoki and Näätämönjoki in Finland (dark-grey colouration). The catchments of the Paatsjoki, Luttojoki and Uutuanjoki are considered as buffer zones (black colouration). Countries where the status of G. salaris is unknown are left in white. Country codes are given in Table 1