The demographics (e.g. hatch time, growth and mortality) and habitat (macrohabitat and mesohabitat) use of age‐0 blue catfish Ictalurus furcatus (Lesueur) were evaluated in the un‐impounded reach of the middle Mississippi River during 2003–2010. Each year, island complexes and adjacent main river habitats were trawled, and 7,373 age‐0 blue catfish (10–144 mm total length) were collected. Blue catfish hatch timing varied slightly across years and generally began in June and ended in August. Age‐0 blue catfish growth rates and instantaneous mortality rates differed among years. Catch rates of age‐0 blue catfish were highest in side channels and around islands, whereas main channel habitats were infrequently occupied. Regarding mesohabitat use, age‐0 blue catfish frequently occupied low velocity areas (i.e. 0.3–0.4 m/s) of shallow depth (i.e. 1–4 m) and sand substratum. This study has provided insight into age‐0 blue catfish population dynamics and has highlighted the importance of specific habitat characteristics in large rivers that may aid in recruitment of this species.

Sauger Sander canadensis are a popular sport fish native to large turbid midwestern rivers and are in decline across much of their range due to habitat loss and exploitation. Specifically, within the lower Kaskaskia and Ohio rivers, Sauger are managed under different harvest regulations and a knowledge gap exists regarding the current status of both populations as well as the effects of the harvest regulations on the size and age structures of both populations. We collected Sauger by nighttime boat electrofishing during early winter 2014-2016 and used otoliths to age all fish. Sauger stocks in both rivers exhibited fast growth rates and high annual mortality rates. Yield-per-recruit modeling indicated that the current 356-mm minimum size limit for Sauger in the Kaskaskia River is sufficient to prevent growth overfishing and likely explains the consistently larger size structure (greater proportion of fish !356-mm total length) of Sauger sampled from the Kaskaskia River compared with the Ohio River. Modeling suggested that growth and recruitment overfishing of Sauger are likely occurring in the Ohio River with no minimum length limit based on available exploitation estimates for Sauger in the lower Ohio River. Implementing a 356-mm minimum length limit for Sauger in the lower Ohio River is predicted to prevent growth and recruitment overfishing based on available exploitation rate estimates and would be consistent with the statewide minimum length limit for Sauger in Illinois and minimum length limits on two major tributaries (Tennessee and Cumberland rivers downstream of Kentucky and Barkley lakes, respectively).