Important characteristics determining the success of nonnative freshwater fish introduction, establishment, and impact.

AimThe invasion success of introduced freshwater fish is influenced by many factors, including ecological, species, and socioeconomic characteristics. Most studies that document the importance of one of these factors are conducted at a local scale and/or focus on a single step of the invasion process. Here, our aim is to identify the characteristics of successful invaders across the entire invasion process using ecological, species, and socioeconomic characteristics.LocationWorldwide.Time periodContemporary.Major taxa studiedFreshwater fish.MethodsWe conducted a worldwide analysis of 307 freshwater fish species and considered the number of countries in which each species was introduced, established, or had ecological impacts as a proxy of invasion step success. We applied generalized linear models to 20 variables relating to species morphology, ecology, and introduction pathways to determine the main characteristics associated with invasion success. By disentangling our results by pathways, we specifically explore the role played by aquaculture and ornamental trade pathways in the characteristic selection.ResultsWe found that non-native freshwater fish with a broad diet, high parental care, and multiple introduction pathways are the most widely introduced and established worldwide. The number of countries associated with impacts was best explained by the type of introduction pathway (i.e., aquaculture or fisheries). We also discovered that alien species introduced through aquaculture belonging to Cypriniformes and having a broad diet were the most widely introduced and established species. The same was observed for species introduced through ornamental pathways that were mainly native to tropical regions.Main conclusionsConsidering both intrinsic and extrinsic drivers is important when analyzing the invasion success of freshwater fish and disentangling the different invasion steps. These findings have strong implications for anticipating the profile of species with a high potential to invade a large number of countries.