Stocking of eggs is a common strategy to support declining or reintroduce extirpated salmonid populations. Data on how juveniles disperse from stocking points is crucial to be able to design efficient stocking programs. Detailed information of dispersal is limited for many salmonids, for example, brown trout. In this study, dispersal distance was measured at the end of the first growing season in a low gradient (0.7%) stream in Sweden where the trout population had been depleted. Eggs from 17 separate sets of parents were stocked as eyed eggs in March. During the following fall fry were sampled throughout the stream. The majority of the fry dispersed downstream and remained within a distance of 200 m from the stocking point with no difference between sizes of fry and the presence of a competing cohort or not. There was no dissimilarity in dispersal distances across offspring originating from different parents indicating absence of genetic influence. Our results suggest that, in streams similar to our study site, stocking points should be separated by approximately 330 m in order to avoid overlap in habitat use of fry from different stocking points and that the presence of competing cohorts, fry size and within population variability in dispersal can be neglected.

Artificial spawning habitat has been used to mitigate for lost habitat and to increase the abundance of salmonids, but the endurance and potential need of maintenance of these habitat improvements have not been well studied. We studied the movement of gravel, attributed to spawning activity of brown trout in a third‐order stream in northern Sweden by deploying PIT‐tagged grains of gravel on artificially constructed gravel patches. The results suggest that gravel movement was substantial and most prevalent at the central parts of the patches. As 76% of the tagged gravel was mobilized during a single spawning season, maintenance of this habitat improvement may be necessary in order to guarantee its functionality over time. This study provides a first step in guiding managers tasked with identifying factors degrading restored spawning habitat and maintenance needed.