Assessing the occurrence of egg stranding for trout and salmon in a regulated river

Abstract A key challenge in many regulated rivers is to define adequate flow levels protect aquatic organisms. Provisioning of suitable can be pivotal bottlenecks for fishes such as salmon and trout that use the riverbed an incubation habitat. Additionally, locations where females spawn will probability embryos dewatered during period a regime. We investigated water flow, dewatering, mortality Atlantic brown natural nests over 19 years Bjoreio River western Norway. During study period, different strategies were applied mitigate dewatering incubating embryos. Average survival sampled late winter ranged from 54% 92% among was significantly correlated with minimum occurring period. Mortality higher shallow areas, reflecting exposed dewatering. The results demonstrate strong link between managed regimes river spawning salmonids. Using detailed information on nest location mortality, we estimate requirements this approach effectively impact regulations embryo trout.