Identifying Overall, Seasonal, and Diel Patterns for Reservoir-Wide Distribution of Blue Catfish: Filling Critical Gaps for Fish Ecology and Fisheries Management

The failure to understand system-wide distribution of mobile fish predators has impeded progress in fish ecology and limited the effectiveness of fisheries management. Biotelemetry innovations offer new hope for filling these critical information gaps. Here we combine acoustic tags with stationary receivers to quantify the reservoir-wide distribution of Blue Catfish (Ictalurus furcatus) using three metrics (population proportion, residence time, and movements). Then we test if season and diel period alter distributional patterns. From June-November, 2012-2013, we tracked 123 acoustically tagged (VEMCO V9-V13) Blue Catfish (mean: 505.3 mm TL; SE: 12.3 mm; range: 300-1090 mm) in Milford Reservoir, KS. Tagged blue catfish were consistently clustered in the lower-upper and upper-middle reservoir regions. Tagged catfish used locations defined by (a) large, active aggregations, (b) exploration/transition, (c) small, sedentary aggregations, or (d) low use. Although some fish moved into the deeper part of the reservoir in the fall, not all tagged catfish moved south nor did all migrators move to the same extent. Few differences in distribution were observed across diel periods. Our approach to looking at whole system distribution provided new insights into the complexity of sportfish predators that can guide future ecological research and increase the effectiveness of fisheries management.