This interrupted case study explores how climate change is impacting the distribution and abundance of fish species, how fishers and fishing communities are adapting to shifts in species ranges and abundances, and how we can effectively manage fish species given the changing environment. The storyline centers on “Captain Joe Fraser,” a fisherman who recognizes changes in his catch and eventually determines that fish populations are shifting their locations as ocean waters become warmer. Students engage in systems thinking to understand the relationship between the environment and human activities, identify patterns and trends, and recognize how a system’s structure causes its behavior. This case study works well in entry-level (high school or undergraduate) biology, marine science, ecology, human geography, or environmental science courses; the interdisciplinary content of the case may also make it suitable for an entry-level economics or social science course.