Invaders they are a‐changing^†: A recent, unexpected surge of invasive loaches in Catalonia

Abstract Risk analyses for invasive species often assume that the characteristics of future invaders will resemble those already successful, but these features may change. Here, we use data from more than 3,500 fish sampling events, sequencing mitochondrial and nuclear genes several traits describing non‐native to describe irruption rapid expansion loaches in Catalonia, north‐east Iberian Peninsula, framing this surge knowledge previous invasions. We report establishment at least five ( Cobitis bilineata , Misgurnus anguillicaudatus bipartitus Paramisgurnus dabryanus a yet undescribed Barbatula species) loach most which are currently spreading. Furthermore, one two regionally native paludica ) has been introduced is spreading through river basins where it not native. Genetic were fundamental understand invasions, by clarifying specific statuses, identifying origin populations and/or detecting independent introduction events. results also highlighted unresolved taxonomy loaches, particularly European . Loaches recent, diverse, successful whose differ previously established species, signalling potential weaknesses prevention biological invasions based on prohibited lists. call development flexible management tools (e.g. only identities) prioritising responses new introductions.