The demographic responses of long-lived endangered species to climate variability can be complex. Nonlinearities in physical and biological processes can obscure relationships between changes in climate and corresponding demographic responses. Efforts to conserve such species will require an understanding of the multi-tiered mechanisms linking climate variability to ecosystem processes and population dynamics. Here, we describe the physical-biological coupling of oceanographic processes linking climate variability to the reproduction of North Atlantic right whales. These findings suggest that future climate change, through its regional effects in the Northwest Atlantic, may emerge as a significant factor influencing recovery of this highly endangered species.