This “condition report” provides a summary of resources in the Thunder Bay National Marine Sanctuary (sanctuary)1, pressures on those resources, current conditions and trends, and management responses to the pressures that threaten the integrity of sanctuary resources. Specifically, the document includes information on the status and trends of water quality, habitat, living resources and maritime archaeological resources, and the human activities that affect them. It presents responses to a set of questions posed to all sanctuaries (Appendix A). Resource status of Thunder Bay is rated on a scale from good to poor, and the timelines used for comparison vary from topic to topic. Trends in the status of resources are also reported, and are generally based on observed changes in status over the past five years, unless otherwise specified.