Seasonal and Diel Patterns of Depth and Temperature Distribution of Blue Catfish in Milford Reservoir, KS

Most fish telemetry studies focus on horizontal movements through space and time.  With recent advances in tag technology, the vertical and temperature distribution of tagged fish can also be explored.  This study examined depth [measured as (1) meters from surface, (2) meters from the bottom, and (3) water column proportion] and temperature (°C) at which ten Blue Catfish (Ictalurus furcatus), implanted with temperature-depth acoustic transmitters, were tracked from June to November, 2012. Most Blue Catfish exhibited a seasonal shift in depth from shallow in summer to deep in fall (measured as depth from surface). This change was due to a horizontal shift from upstream shallow sites in the summer to downstream deep sites in the fall as other measures of depth (distance from the bottom or water column) did not change seasonally. Blue Catfish exhibited diel vertical movement patterns in which fish were closer to the bottom during the day and farther from the bottom at night. Individual Blue Catfish experienced different temperatures within a day (max, min, and range), indicating facultative temperature selection. Understanding how fish use the water column and available temperatures can improve our understanding of fish ecology and provide information useful for fish management.