Data from - Asian loaches: An emerging threat as global invaders

The introduction of non-native species is a major driver of biodiversity loss and poses a growing threat to the health and functioning of freshwater ecosystems globally. In recent decades, the pet trade and aquarophilia have become lucrative industries, accelerating the spread of new non-native fishes. This includes various species of Asian loaches that have recently been detected outside their native range in several European countries as well as in the United States and Australia. Using species distribution models, we aim to evaluate the potential of the large-scale loach Paramisgurnus dabryanus and the dojo weatherloach Misgurnus anguillicaudatus to become globally invasive, and explore their impacts on the threatened European weatherfish Misgurnus fossilis. Our results indicate that both loaches have a high potential to become globally invasive, with M. anguillicaudatus appearing more capable of invading broader areas than P. dabryanus. Identified as most vulnerable were temperate regions in Europe, North America, and the south-eastern coast of Australia. The range expansion of these two Asian loaches in Europe could significantly increase their distribution overlap with populations of the native M. fossilis, with projections showing P. dabryanus increasing from a current overlap of 0.5% to 11.8% and M. anguillicaudatus from 0.9% to 90.5%. These findings highlight that the introduction of non-native loaches can pose a substantial threat to M. fossilis, but also other native and especially benthic fishes, as well as macroinvertebrate prey. To halt the spread of these highly invasive fishes, it is essential to prevent new introduction events and conduct further research on their ecology and current global distribution.