title: Impact of beaver dams on abundance and distribution of anadromous salmonids in two lowland streams in Lithuania.
abstract: European beaver dams impeded movements of anadromous salmonids as it was established by fishing survey, fish tagging and redd counts in two lowland streams in Lithuania. Significant differences in abundancies of other litophilic fish species and evenness of representation by species in the community were detected upstream and downstream of the beaver dams. Sea trout parr marked with RFID tags passed through several successive beaver dams in upstream direction, but no tagged fish were detected above the uppermost dam. Increase in abundances of salmonid parr in the stream between the beaver dams and decrease below the dams were recorded in November, at the time of spawning of Atlantic salmon and sea trout, but no significant changes were detected in the sections upstream of the dams. After construction of several additional beaver dams in the downstream sections of the studied streams, abundance of Atlantic salmon parr downstream of the dams decreased considerably in comparison with that estimated before construction.
authors: Department of Freshwater Biology, Nature Research Centre, Vilnius, Lithuania.
authors: Tomas
authors: T
authors: Virbickas
authors: Department of Freshwater Biology, Nature Research Centre, Vilnius, Lithuania.
authors: Saulius
authors: S
authors: Stakėnas
authors: Department of Freshwater Biology, Nature Research Centre, Vilnius, Lithuania.
authors: Andrius
authors: A
authors: Steponėnas
mesh_terms: D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D008097:Lithuania; D009425:Nesting Behavior / Q000502:physiology*; D011157:Population Dynamics; D057233:Radio Frequency Identification Device; D045483:Rivers; D012377:Rodentia / Q000502:physiology*; D012487:Salmonidae / Q000502:physiology*; D013045:Species Specificity; D018709:Statistics, Nonparametric; D014872:Water Movements