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Above‐normal precipitation in the 1990s resulted in new waters and Walleye Sander vitreus fisheries across northeastern South Dakota. Concerns with overharvest led to the implementation of a Walleye minimum length limit (MLL) on many new fisheries, but over time most of the MLLs were removed. We were interested in knowing why the MLLs failed. We compared Walleye gill‐net data and angler creel data under rising and declining water regimes and between periods with and without an MLL regulation in two new waters (Bitter Lake and Waubay Lake). We also assessed Walleye annual recruitment and growth patterns and examined if water regimes, MLLs, or Walleye recruitment were potential drivers of Walleye relative abundance, growth, and size structure. Few differences were found across water regimes and between periods with and without an MLL. At Bitter Lake, significant differences were identified across water regimes for the number of age‐3 Walleyes per gill net, Walleye proportional size distribution of preferred length (PSD‐P), angling pressure, and angler catch rates of Walleyes. Walleye relative weight and PSD‐P significantly differed between water regimes at Waubay Lake. Mean length at capture for age‐3 Walleyes and proportional size distribution were significantly different between periods having an MLL and no MLL at Bitter Lake. At Waubay Lake, Walleye gill‐net CPUE (number/gill net) and PSD‐P significantly differed between periods with and without an MLL. Water regimes, MLL, and Walleye recruitment were not identified as strong drivers of Walleye population characteristics. Recruitment was variable in each lake (Bitter Lake age‐3 CPUE CV = 148%, Waubay Lake age‐3 CPUE CV = 166%), with occasional strong cohorts recruiting. We believe recruitment dynamics influenced Walleye abundance and growth, which led to the removal of MLLs from each lake. Knowledge concerning Walleye population recruitment dynamics and growth is important when implementing MLLs and evaluating their effectiveness. [ABSTRACT FROM AUTHOR]

The rudd (Scardinius erythrophthal,nus) was first identified in South Dakota waters during the early 1990's. Since its introduction, there has been a paucity of information concerning its presence. The objectives of this research were to summarize rudd collections in South Dakota, to describe the population dynamics of three established populations, and to assess possible effects on native fish communities. Rudd have been collected from waters in nine South Dakota counties and one Missouri River reservoir. Lake Alice, Newell Lake, and Sheridan Lake currently have self-sustaining rudd populations. Rudd relative abundance has stabilized in these three lakes. Population samples were dominated by individuals >200 mm total length. Recruitment has been consistent with several year classes present in each lake and natural mortality tends to be low. Rudd growth rates in Lake Alice and Newell Lake were extremely fast. It currently does not appear that the fish communities have been adversely affected by the presence of rudd. [ABSTRACT FROM AUTHOR]