Stream habitat restoration is an important tool for fisheries management in impaired lotic systems. Although small‐scale benefits of stream habitat restoration are commonly investigated, it is difficult to demonstrate population effects. The Pahsimeroi River Chinook salmon Oncorhynchus tshawytscha population was previously restricted to the lower portion of the river by multiple irrigation structures. To address fish passage issues, a combination of restoration projects was initiated including barrier removals, instream flow enhancements and installation of fish screens on diversions. The largest barrier was removed in 2009, more than doubling the amount of accessible linear habitat. We hypothesized restoration efforts would expand the distribution of spawning salmon in the Pahsimeroi River watershed, leading to a broader distribution of juveniles. We also hypothesized a broader juvenile distribution would have population effects by reducing the prevalence of density‐dependent growth and survival. Redds were documented in newly accessible habitat immediately following barrier removal and accounted for a median of 42% of all redds in the Pahsimeroi River watershed during 2009–2015. Snorkel surveys also documented juvenile rearing in newly accessible habitat. Juvenile productivity increased from a median of 64 smolts/female spawner for brood years 2002–2008 to 99 smolts/female spawner for brood years 2009–2014. Overall, results suggested increased habitat accessibility in the Pahsimeroi River broadened the distribution of spawning adult and rearing juvenile salmon and reduced the effects of density‐dependent survival. Large‐scale stream restoration efforts can have a population effect. Despite the large‐scale effort and response, habitat restoration alone is likely not sufficient to restore this population.

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Recruitment is an important driver of fish population abundance and size structure and can be affected by a variety of density-dependent and density-independent factors. Walleye Sander vitreus populations often exhibit variable yearclass strength, which has been attributed to a suite of factors. In this study, we quantified variability in Walleye recruitment, assessed within-lake recruitment synchrony, and modeled recruitment variability for year-classes that were produced from 1988 to 2013 in Lake Oahe, a large Missouri River reservoir. The objectives of this study were to determine (1) whether Walleye recruit annually, (2) whether Walleye recruitment is spatially synchronous, and (3) whether Walleye recruitment is better described by biotic or abiotic factors. The variability of Walleye recruitment was indexed by using gill-net catch of age-2 Walleye across nine locations in Lake Oahe, and factors affecting recruitment were evaluated by using stock-recruit analysis. Over the 26 years that were assessed, all year-classes were present and four exceptionally large year-classes were produced. Recruitment synchrony was apparent among locations within Lake Oahe, but this relationship was largely influenced by the spatial synchrony of the four exceptionally large year-classes and was no longer detectable when those year-classes were removed. The relative abundance of age-4 and older Walleye, taken as an index of spawner abundance, was a poor predictor of Walleye recruitment, indicating that Walleye recruitment was regulated by density-independent factors across the range of observations. The interactive effects of reservoir elevation and elevation change improved model fit to explain 59% of the recruitment variation and indicated that increased elevation from the previous year improved recruitment. Our results indicate that Walleye recruitment may be favored by increasing the water levels in the reservoir in spring. Recruitment is often the most variable rate that influences the abundance and size structure of fish populations (Gulland 1982; Allen and Pine 2000; Hansen and Nate 2014). Year-class strength and subsequent recruitment to a fishery can be influenced by density-dependent effects on juvenile production and survival as well as many densityindependent abiotic and biotic factors. Spawner abundance may influence recruitment through compensatory density dependence, with high juvenile survival at low spawner abundance and low juvenile survival at high

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