Top predators can change their distribution in response to resource availability. In so doing, these motile animals can influence their own growth, survival, and fitness. Blue catfish is a model species with which to examine whole system distribution because this large-bodied, long-lived predator is the most mobile of the North American catfish. In this research, we developed and tested tagging protocols, acoustically tagged the most common size of young-adult catfish, tracked tagged fish with continuously-operating stationary receivers, conducted a lake-wide manual tracking survey, and quantified spatially-explicit distributional patterns and drivers of those patterns. This research matters because blue catfish, as a top fish predator, can have influential ecosystem effects and are an important sportfish. In a nutshell, our fisheries management colleagues cannot successfully manage blue catfish without the spatial data described above. Our partners for this research were the Kansas Department of Wildlife, Parks, and Tourism. This research informs decisions. Our tagging and sample design allowed us to detect an unprecedented number of time-space locations (i.e., millions of fish detections) over the course of the 2-year field study. This success allowed us to track 85% of tagged catfish over a 5-month annual field season. In addition, we combined three different site-specific responses (population number, residence time, movements) to reveal novel patterns of whole system distribution. For example, many fish constantly moved through Milford reservoir, but returned regularly to a large, central aggregation. At other sites, fish exhibited traditional site fidelity or exploratory behavior. This result has impact for fisheries managers by providing detailed, quantitative maps of where fish are located and how this changes through time and space. With this information, managers can be more successful in their sampling/assessment, in setting harvest regulations, and in providing information for their core constituency, anglers.
