Understanding, quantifying, and comparing the temporal distribution of anadromous fish spawning migrations is an important yet vexing problem for fisheries research, management, and conservation. Central to this problem is the lack of a representative and comprehensive standardized suite of quantitative metrics to characterize the complex, multidimensional temporal distribution of migrating anadromous fish. Without this, it is not possible to develop effective sampling regimes, extrapolate counts to accurate population estimates, understand the basic ecology and behavior of anadromous fish, or make the comparisons through time and across river systems that are fundamental to sustainable conservation. In this thesis, I define, calculate, and compare 17 metrics that characterize the temporal distribution of migrating adult river herring [two closely related clupeids, the alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis)] as they return to spawn. These metrics are based on fish counts from three southeastern Massachusetts river systems that were obtained through a low-cost video monitoring system.