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.

Smallmouth Bass Micropterus dolomieu, an important sport fish and apex predator, are commonly sampled by fisheries personnel using night electrofishing. We assessed day and night electrofishing catch per hour of effort (CPUE), sampling precision (i.e., CV), and size structure of Smallmouth Bass in eight northeast South Dakota natural lakes during 2013–2016 to determine if day electrofishing was a viable option for population assessment. Night CPUE was generally greater than day CPUE in paired samples. Significant differences in CPUE for fish ≥ 180‐mm TL were identified in approximately one‐third of lake year comparisons. Day and night CPUE were more likely to be significantly different in fish < 350 mm‐TL. A significant linear relationship was identified between day CPUE and night CPUE for all fish. Coefficients of variation of CPUE were similar between day and night samples. Significant differences in proportional size distribution (PSD) were identified for 6 of 15 day–night pairs, but no pattern was identified and no differences in proportional size distribution of preferred‐length fish (PSD‐P) values were found. A linear relationship was identified between day and night PSD and day and night PSD‐P, and neither relationship differed from the 1:1 line. A significant curvilinear relationship was present between the percent deviations (PD) of day and night CPUE across Secchi depths. We believe that day electrofishing can be used to assess Smallmouth Bass populations in eastern South Dakota natural lakes. Received January 9, 2017; accepted July 3, 2017 Published online October 11, 2017

The collection of Walleye Sander vitreus eggs to meet stocking needs is an essential part of Walleye management for many state and provincial agencies. The stress of capture, holding, and stripping gametes from wild broodstock can potentially lead to Walleye mortality. In waters < 1,200 ha, high levels of mortality could alter population size structure and affect angler success, future egg collections, and survival of stocked Walleyes. We quantified shortterm (i.e., 5 d) mortality of female Walleyes during artificial spawning operations during 2015 to 2017 in four eastern South Dakota natural lakes (Swan Lake in 2015, Long Lake in 2016, and Antelope Lake and Reid Lake in 2017). Each year 25 female Walleyes were stripped of their eggs and 25 additional female Walleyes were included as reference fish. No Walleyes died in 2015, four fish that were stripped of eggs at Long Lake died in 2016, and one stripped of eggs at Reid Lake died in 2017. Overall short-term mortality was low (5 of 73 fish, 6.8%) during the study. No reference fish expired during the 3 years. Contusions were apparent on ovaries of both egg-stripped and reference fish. We believe that if fisheries personnel follow standard artificial spawning procedures for Walleye the amount of mortality will be low and should not impact populations of mature female Walleyes.

Walleye Sander vitreus, Sauger S. canadensis, and Yellow Perch Perca flavescens (referred to as percids herein) are collectively among the most culturally and ecologically important fish species in North America. As ecosystems change in response to environmental drivers, such as climate change, nutrient loading, and invasive species, there is a need to understand how percid populations respond to these changes. To address this need, a symposium was held during the 81st Annual Midwest Fish and Wildlife Conference to bring fishery scientists and managers together to describe and discuss percid population responses to ecosystem change. Prevailing symposium themes included the challenge of identifying mechanisms responsible for population‐level changes, developing strategies to adaptively manage for resilient fisheries, and consideration of scale, context, and methods when interpreting variable results. Given the uncertainty of how ecosystem changes affect percid populations, participants emphasized the importance of communicating uncertainties to stakeholders, implementing data‐driven management strategies, setting realistic goals, and revising management actions in an adaptive framework. There was universal agreement on both the challenge and necessity of facilitating constructive engagement among stakeholders in cooperative decision making. Symposium participants identified knowledge gaps and discussed future efforts to build on our current understanding of percid populations, including continuation of long‐term monitoring, improved standardization of evaluation metrics, implementing adaptive management experiments to identify causal relationships, development of more robust analytical methods, use of historical data sources, and refining techniques to realistically convey management options to stakeholders.