Knowing when, where and why animals move is fundamental to our understanding of animal ecology, but also for our ability to conserve biodiversity. Whether to examine the habitat use of wolves in the Rocky Mountains or investigate the migratory routes of fish moving in and out of Danish waters, tracking the movement of animals is crucial to their protection, and in some cases, their sustainable harvest. But how do we monitor aquatic animals, when technology like GPS doesn’t work underwater? Together, we’ll explore how we use telemetry to track what fish do below the surface, and how we use that data within the context of management and conservation. From rivers to the wide ocean, we’ll dig into stories from trout, salmon, bluefin tuna, and more. The aquatic realm is full of life, and there’s many lessons this life can teach us. Let’s dive in.