The ocean provides a bounty of essential life-supporting services. Yet, a changing climate and increasing human uses are altering marine ecosystems and their ability to continue to provide this wealth of essential services. Off the coast of California, we are lucky to have one of the worlds longest-running marine observation programs, the California Cooperative Oceanic Fisheries Investigations (CalCOFI), which has continuously and comprehensively sampled the marine environment off the California coast since 1949 to monitor the indicators and impacts of El Nino and climate change and to support effective marine management. Join marine ecologist and California Sea Grant extension specialist Erin Satterthwaite as she tells the story of CalCOFI through a series of case studies documenting how CalCOFI has been used to understand and address human and natural impacts on marine life along the California coast. (#37033)