Do brown trout (Salmo trutta L.) move streambed substrate?—Implications for durability and maintenance of artificial spawning habitat

Abstract

AbstractArtificial 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.