Seminar title: A tale of two species (and six lakes): disentangling drivers of fish population dynamics across biophysical gradients | Abstract: Freshwater ecosystems are critical for supporting biodiversity and human communities. Inland fisheries provide food and economic security for billions worldwide, but freshwater fishes face a myriad of threats in this era of accelerating ecosystem change. Increased understanding of the causes and consequences of variability in recruitment—a fundamental biological process governing the status and trajectory of populations—is needed to develop effective strategies for sustaining fish populations and fisheries. My dissertation examined the early life-history, recruitment dynamics, and drivers of recruitment variability of two ecologically, culturally, and economically significant fishes: Cisco (Coregonus artedi) and Lake Whitefish (C. clupeaformis). Specifically, I characterized and compared the dynamics of each species across each of the Laurentian Great Lakes, which comprise the largest freshwater ecosystem worldwide and span multiple gradients of biophysical ecosystem structure and anthropogenic disturbance. The results of this research advanced understanding of the biophysical processes regulating recruitment of each species, including evaluating how their relative importance is determined by ecosystem context and identifying which may serve as major recruitment bottlenecks. Importantly, this research provides actionable insights into how recruitment responded to past perturbations and may respond to future climatic and ecosystem change.