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We used direct observation via snorkeling surveys to quantify microhabitat use by native brook (Salvelinus fontinalis) and non‐native brown (Salmo trutta) and rainbow (Onchorynchus mykiss) trout occupying natural and restored pool habitats within a large, high‐elevation Appalachian river, United States. Permutational multivariate analysis of variance (PERMANOVA) and subsequent two‐way analysis of variance (ANOVA) indicated a significant difference in microhabitat use by brook and non‐native trout within restored pools. We also detected a significant difference in microhabitat use by brook trout occupying pools in allopatry versus those occupying pools in sympatry with non‐native trout—a pattern that appears to be modulated by size. Smaller brook trout often occupied pools in the absence of non‐native species, where they used shallower and faster focal habitats. Larger brook trout occupied pools with, and utilized similar focal habitats (i.e. deeper, slower velocity) as, non‐native trout. Non‐native trout consistently occupied more thermally suitable microhabitats closer to cover as compared to brook trout, including the use of thermal refugia (i.e. ambient–focal temperature >2°C). These results suggest that non‐native trout influence brook trout use of restored habitats by: (1) displacing smaller brook trout from restored pools, and (2) displacing small and large brook trout from optimal microhabitats (cooler, deeper, and lower velocity). Consequently, benefits of habitat restoration in large rivers may only be fully realized by brook trout in the absence of non‐native species. Future research within this and other large river systems should characterize brook trout response to stream restoration following removal of non‐native species. [ABSTRACT FROM AUTHOR]

Large-scale culvert replacement programs could benefit migratory fish populations by reconnecting reproductive and foraging habitats in fragmented watersheds. The objectives of this study were to: (1) identify stream and culvert characteristics contributing to fish passage barriers within an Appalachian watershed, U.S.A.; (2) quantify the total amount of Brook trout ( Salvelinus fontinalis) reproductive habitat isolated above culverts; and (3) use an ecological currency to identify culvert replacement priorities and stream mitigation credit opportunities. We surveyed 120 state-owned culverts and used a fish passage assessment filter to determine the “passability” of each culvert. We then constructed a geographic information system stream network model to quantify the amount of trout reproductive habitat isolated by culverts. Ninety-seven percent of surveyed culverts were classified as obstacles or complete barriers to trout dispersal. Culvert impassability was higher in small streams with slopes exceeding 3–5%, suggesting a direct relationship between slope and impassability. Thirty-three percent of Brook trout reproductive habitat, representing over 200 km of stream, was isolated by culverts. This is a conservative estimate, because we did not survey privately or federally owned culverts. The top 20 prioritized culverts accounted for nearly half of the habitat loss. Our results indicate that standard culvert designs placed in streams with slopes exceeding 5% consistently produce trout dispersal barriers and should be avoided during new road construction. The process developed here provides an efficient method for identifying culvert replacement priorities and may be used to maximize watershed scale benefits of stream restoration. [ABSTRACT FROM AUTHOR]

1. We used direct observation and mark-recapture techniques to quantify movements by mottled sculpins (Cottus bairdi) in a 1 km segment of Shope Fork in western North Carolina. Our objectives were to: (i) quantify the overall rate of sculpin movement, (ii) assess variation in movement among years, individuals, and sculpin size classes, (iii) relate movement to variation in stream flow and population size structure, and (iv) quantify relationships between movement and individual growth rates. 2. Movements were very restricted: median and mean movement distances for all sculpin size classes over a 45 day period were 1.3 and 4.4 m respectively. Nevertheless, there was a high degree of intrapopulation and temporal variation in sculpin movement. Movement of juveniles increased with discharge and with the density of large adults. Movement by small and large adults was not influenced by stream flow, but large adults where more mobile when their own density was high. Finally, there were differences in the growth rates of mobile and sedentary sculpins. Mobile juveniles grew faster than sedentary individuals under conditions of low flow and high density of large adults, whereas adults exhibited the opposite pattern. 3. Our results support the hypothesis that juvenile movement and growth is influenced by both intraspecific interactions with adults and stream flow. In contrast, adult movement appears to be influenced by competitive interactions among residents for suitable space. The relationship between movement and growth may provide a negative feedback mechanism regulating mottled sculpin populations in this system. [ABSTRACT FROM AUTHOR]