Freshwater Fish Invasions: A Comprehensive Review

Freshwater fish have been widely introduced worldwide, and freshwater ecosystems are among those most affected by biological invasions. Consequently, freshwater fish invasions are one of the most documented invasions among animal taxa, with much information available about invasive species, their characteristics, invaded regions, invasion pathways, impacts, and management. While existing reviews address specific aspects of freshwater fish invasions, there is still a gaping lack of comprehensive assessments of freshwater fish invasions that simultaneously address pivotal and connected elements of the invasion process. Here, we provide a holistic review, together with quantitative assessments, divided into four major parts: ( a) introduction pathways, ( b) characteristics of nonnative species andinvaded ecosystems that explain successful invasion processes, ( c) invasion impacts and their mechanisms, and ( d) management. We highlight data gaps and biases in the current databases and highlight a basic lack of understanding of several aspects of freshwater fish invasions. In addition, we provide recommendations for future studies.