Drivers of the range expansion of the European catfish (Silurus glanis) within its native distribution.

The European catfish Silurus glanis L. continues to spread as an invasive species in Europe. Meanwhile, increasing abundance and range expansions are also suspected within its native distribution. The objective of this study was to characterize the feeding, growth and abundance of S. glanis in 12 lakes and 12 rivers within its European native range in relation to environmental changes that may explain population trends over time. The results suggest a shift in factors limiting the carrying capacity of catfish habitats within this range, leading to increases in growth and abundance. Statistical modelling identified warming and increasing population density of invasive gobies as likely contributors to this shift. Given that catfish predation on native species can be expected to increase dramatically, there is an urgent need for new management strategies. It is recommended that catfish removal rates should be increased, especially in areas of high importance for native fish and crayfish species, such as spawning grounds and at bottlenecks for migration.