Paddlefish (Polyodon spathula) are a commercially-exploited species harvested primarily for their roe. e objectives of this study were to describe population characteristics of paddlefish in the lower Mississippi River (LMR) of Arkansas and use population-simulation so ware to deter- mine the length limit required to prevent recruitment over fishing by maintaining spawning potential ratios (SPR) over 30%. Paddlefish (n = 534) were collected from the LMR in cooperation with commercial fishers during the 2008–2011 commercial seasons. Lengths ranged 150–1095 mm eye-fork length and ages, 2–24 years. Total annual mortality was estimated from catch curves at 28%, and mean instantaneous natural mortality was estimated to be 0.19, conferring an estimated exploitation of 10%. Only 10% of gravid females were under the existing 864-mm minimum-length limit (MLL), but changing the MLL to 889 mm would protect an additional 10%. Growth models predicted that fish required 10.8 and 11.8 years to reach 864 mm and 889 mm, respectively. Population simulations predicted higher roe yields for 899- and 916-mm MLL compared to the existing 864-mm MLL. e threat of recruitment over fishing appeared to be low at 10% exploitation rate for all MLLs. Based on the results of this study, the Arkansas Game and Fish Commission instituted an 889-mm MLL in 2013 to protect the sustainability of the paddle fish population in the LMR. As of 2016, the effectiveness of this regulation had not been assessed yet due to lack of funding.