| Abstract |
Beaver (Castor canadensis) translocation and mimicry is an increasingly popular set of tools for process-based restoration of degraded streams. Previous studies indicate that spring-spawning salmonid fishes can pass beaver dams in higher proportions than fall-spawning species. Thus, restoration or mimicry of beavers in streams containing threatened, fall-spawning bull trout (Salvelinus confluentus) is of concern to many biologists. We evaluated bull trout passage at beaver dams in two Montana streams: Meadow Creek (East Fork Bitterroot River drainage) in summer 2020 and Morrison Creek (Middle Fork Flathead River drainage) from 1997 to 2011. In Meadow Creek, 16% of PIT-tagged bull trout which entered a large beaver dam complex were detected upstream of some dams, but no fish moved through the entire 1 km complex. The redds in Morrison Creek occurred below beaver dams in higher proportion than if random spawning-site selection had occurred. Redds were found above some beaver dams during all 9 years dams were present. These results suggest that beaver dams can affect the movement of bull trout and that passage depends on the characteristics of individual dams and reach geomorphology, though our methods cannot distinguish between inhibition of fish movement and selection of beaver-created habitats by fish due to the limited data we had on spawning habitat. Therefore, we suggest future beaver restoration in streams with bull trout be carefully monitored and conducted in an adaptive framework. Comparing spawning-site selection and fish movement in streams with and without beavers may provide additional information. |
| Authors |
J. Marshall Wolf  , Niall G. Clancy  , Leo R. Rosenthal
|
| Journal Info |
Washington State University Press | Northwest Science , vol: 97
, iss: 1-2
|
| Publication Date |
6/18/2024 |
| ISSN |
0029-344X |
Type |
article |
| Open Access |
closed
|
| DOI |
https://doi.org/10.3955/046.097.0108 |
| Keywords |
Beaver Dams (Score: 0.628653)
|
