Do non-native pumpkinseed Lepomis gibbosus affect the growth, diet and trophic niche breadth of native brown trout Salmo trutta?

Abstract

Brown trout Salmo trutta Linnaeus, 1758, is a priority species for conservation and management efforts in many European countries. In its native range, interactions with non-native fishes often adversely affect somatic growth rates and population abundances. Consequences of introduced North American pumpkinseed Lepomis gibbosus (Linnaeus, 1758) for native S. trutta were examined in stream stretches with and without L. gibbosus. Data for somatic growth rates and trophic niche breadth (using stable isotope L. gibbosus for S. trutta in the study stream were minimal, with S. trutta populations responding more to natural mechanisms regulating their populations than to the presence of this non-native fish species.