Spoiled for Choice during Cold Season? Habitat Use and Potential Impacts of the Invasive <i>Silurus glanis</i> L. in a Deep, Large, and Oligotrophic Lake (Lake Maggiore, North Italy)

Abstract

The ecological features of invasive alien species are crucial for their effective management. However, they are often lacking in newly invaded ecosystems. This is the case of the European catfish Silurus glanis L. in Lake Maggiore, where the species is present since 1990, but no scientific information is available on its ecology. To start filling this knowledge gap, 236 catfish (67 cm to 150 cm of total length) were collected, measured, and dissected for stomach content analyses from three localities and in two habitats (littoral vs. pelagic) in late autumn/early winter. The NPUE and BPUE (individuals (N) and biomass (B, in grams) per unit effort (m2), respectively) of catfish were generally higher in littoral (NPUE > 0.01; BPUE > 96) than in pelagic habitats (NPUE S. glanis may have for the lake’s fishery.

Keywords

• trophic ecology
• ecological plasticity
• European catfish
• pelagic habitat
• littoral habitat
• commercial fishermen