The study reveals that anoxic conditions in the transition zones between rivers and reservoirs are detrimental to the recruitment of the endangered Pallid Sturgeon. This anoxic environment results from reduced river velocities and increased concentrations of fine particulate organic material with high microbial respiration. The authors advocate for a broader regulated-river management paradigm that equally considers both upriver and downriver effects of dams to effectively mitigate altered ecosystems, especially for the benefit of large river fishes like Pallid Sturgeon.