Mark Pegg, email@example.com
Blue catfish Ictalurus furcatus are a mobile, large-river species native to the Missouri River and its tributaries, including the Kansas River. Historical data regarding the Kansas River population is negligible, limiting managers’ ability to appropriately manage this population. Multiple anthropogenic barriers along the Kansas River create a gradient of connectivity within the Kansas River, and with the Missouri River, possibly limiting Blue Catfish movement. Additionally, the contribution of tributary reservoir populations to the Kansas River remains unknown. My objectives were to: 1) describe the population characteristics and 2) quantify stock contributions from the Missouri River and Kansas River tributary reservoirs to the lower Kansas River population. Relative abundance and condition were variable among years with little variation across the gradient of connectivity. Somatic growth of disconnected reaches were greater than connected reaches; however, the mean length of adult age classes were consistent across the study area. River segments connected with the Missouri River had lower annual mortality and higher proportions of large fish compared to disconnected reaches. Upstream passage was not documented at the second barrier on the Kansas River, suggesting the population upstream of the barrier is isolated from the Missouri River. Adult fish collected within river reaches connected to the Missouri River displayed relatively equal natal contributions from the Kansas River and Missouri River. Half of adult and juvenile fish sampled in reaches disconnected from the Missouri River originated from Kansas River tributary reservoirs. Our data suggests adopting two spatial scales for investigating and managing Blue Catfish in the Kansas River, with the second barrier as a point of division. Current state-wide regulations are adequate for maintaining high trophy-potential in downstream river reaches. The large number of fish using the Missouri River indicates appropriate management requires a broad spatial scale that incorporates a dendritic river network framework. Future monitoring efforts, particularly for the disconnected reaches, is imperative as large reservoir stock contributions may elicit change in population characteristics.
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