Effects of a Hydropower-Related Temporary Stream Dewatering on Fish Community Composition and Development: From Ecology to Policy

Hydropower use of rivers can exert multiple effects on aquatic species and habitats. Due to limitations conservation projects in the main channels hydropower-affected rivers, there has been an increasing focus tributaries, side channels, fish passes as target areas for restoration. However, some these require frequent dewatering their maintenance, ecological such measures remain largely unknown. In this study, we used two events a channel River Inn opportunity assess common fish. All stranded were collected after remaining puddles formerly restored bank habitats, determined level, measured. The community was compared by electrofishing before seven weeks subset same created one three covering 3% assessed habitat area. puddles, 184 from 12 found, including strictly protected under national international law. relation relative abundance, smaller less mobile Cottus gobio mostly affected stranding contrast larger open-water-oriented Chondrostoma nasus . also caused drying out important nursery zones, resulting distinctly lower recruitment success endangered riverine summer following dewatering. evidence about negative documented herein should be transferred into policy reduce impairment minimum contribute fulfilment legal requirements. This achieved reducing extent frequency periodical minimum, slowing down speed, selecting least critical time year, well compensation measures.