Fish in freshwater lakes are experiencing pressures from pollution, invasive species, and changes in physical conditions due to a changing climate. Being able to predict how a population of fish will respond to these pressures, namely climate change, by analyzing long-term data sets will contribute to an improved understanding of how ecosystems are sensitive to disturbance. This project provides analytical methods to disentangle variably in fish catch data, and provides useful methods for detecting trends over time. This will help managers detect and predict impacts of climate change on fish populations, the potential consequences for monitoring programs, and the ability to communicate scientific uncertainties in ways that are useful to decision-makers. The anticipated changes to fish populations in space and time will contribute to more effective monitoring and management of fish in the Great Lakes basin and other freshwater lakes that have experienced large-scale changing conditions.