Historical marine ecology provides information on past ocean conditions and community structure that can inform current conservation and management. In an era of rapid global ocean changes, it is critical that managers and scientists ensure sufficient documentation of past and present conditions of resources they manage or study. Documenting, archiving, and preserving historic and contemporary data will provide their colleagues in the future with more information to make robust science-based management decisions. Using a workshop approach, we identified research and archiving priorities to enhance documentation of the past and present conditions of coastal and marine ecosystems of the northern Channel Islands in California. We identified a variety of historical data types (e.g., archeological data, oral histories, environmental records, imagery) that should be preserved and analyzed to better understand past coastal and marine ecosystems around the northern Channel Islands. Continuing with long-term monitoring programs is also important for establishing baselines to inform contemporary management decisions and compare with future conditions. Herein, we underscore the role that individual scientists and managers working in the northern Channel Islands must play in documenting their work, archiving data, and preserving specimens in museums and institutions. Our case study for the northern Channel Islands provides a guide for how scientists should be documenting past and present conditions for marine resources around the world. Robust documentation of such conditions will give future scientists, managers, and other stakeholders the information needed to navigate what are sure to be increasingly complex management challenges.