Common Carp Cyprinus carpio is a highly invasive species that can alter shallow aquatic ecosystems from clear to turbid water. Although mechanical removals are commonly used to control abundance of adult Common Carp, harvest models suggest that removing age‐0 Common Carp also reduces recruitment. Attractants often improve fisheries sampling and commercial harvest and may provide a tool to increase catch rates of age‐0 Common Carp. However, techniques and attractants that target age‐0 Common Carp have not been evaluated. Our objective was to compare catch rates and size distribution of age‐0 Common Carp captured in cloverleaf traps with and without bait (fish meal or bloodworms) or light attractants. To assess whether trapping decreased the abundance of age‐0 Common Carp, we also evaluated (1) the total number and proportion of age‐0 Common Carp removed from the populations and (2) whether catch rates declined temporally as a result. Traps were fished in emergent vegetation for 5–6 nights in two shallow lakes in South Dakota during August 2010. Catch rates of age‐0 Common Carp did not differ among attractants and the control. However, catch rates declined through time, and 3,102 age‐0 Common Carp were removed from the two lakes. Depletion population estimates indicated at least 83% of age‐0 Common Carp from Brant Lake and 21% (lower limits, 95% confidence intervals) of age‐0 Common Carp from Whitewood Lake were removed, suggesting trapping may be successful at depleting abundance. Lighted traps caught larger age‐0 Common Carp than did control traps or traps baited with bloodworms or fish meal. These results suggest that the attractants evaluated here do not increase catch rates of age‐0 Common Carp. Nonetheless, cloverleaf traps may reduce abundance of age‐0 Common Carp and have value in integrated management plans for this species. Received August 6, 2015; accepted January 6, 2016 Published online May 16, 2016

Field evaluations of management manipulations are rarely conducted, in part because they are difficult to design and require large sampling effort. However, many commonly used management approaches have <50% success rate, indicating the need for more research. Herein, we provide a case study illustrating how historic standard sampling data from Oklahoma were used to design robust before–after control–impact study designs to evaluate the effectiveness of stocking saugeye Sander vitreus × S. canadensis as a predatory control for stunted White Crappie Pomoxis annularis populations. Comparing six manipulated lakes with six reference lakes (no saugeye stockings), we found that proportional size distribution, proportional size distribution of preferred‐size fish, and mean length at ages 1 and 2 of White Crappie all improved after stockings, but still fell short of statewide median values. Further, similar improvements in these metrics also occurred in reference lakes, suggesting they were likely caused by regional patterns (flood/drought or temperature effects) rather than management intervention. Thus, we conclude saugeye stockings are not likely to routinely improve stunted White Crappie fisheries. We encourage managers who have historic data to use these data to robustly evaluate management interventions (as illustrated in this study), because our field needs additional information regarding when management interventions will be most effective, versus when they may not have the desired outcome. These historic data sets have considerable utility in providing this type of information. Our case study illustrates the importance of replication and reference lakes to avoid erroneous conclusions in such evaluations.