Natural Resources, School of
First Advisor
Mark A. Pegg
Second Advisor
Jonathan J. Spurgeon
Committee Members
Malinda Henry, Kirk Steffensen
Date of this Version
12-2024
Document Type
Thesis
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Natural Resource Sciences
Under the supervision of Professors Mark A. Pegg and Jonathan J. Spurgeon
Lincoln, Nebraska, December 2024
Abstract
Pallid Sturgeon (Scaphirhynchus albus) are centenarian, potamodromous, rheophiles that historically occupied the Missouri River and Mississippi River basins. Listed on the U.S. Endangered Species Act in 1990, population declines are attributed to habitat fragmentation and degradation, as well as overharvest, and hybridization. A knowledge gap exists regarding the extent to which tributaries facilitate key life stages for Pallid Sturgeon. This study evaluated the capacity of acoustic telemetry to monitor the movements of Pallid Sturgeon in a shallow, braided tributary to the Missouri River. The specific objectives were to (1) evaluate the environmental variables influencing the performance of acoustic telemetry, and (2) quantify movement, residency, and seasonal space use of adult and sub-adult Pallid Sturgeon in the lower Platte River, Nebraska. Range tests were employed, revealing relatively low detection ranges (< 200 m) compared to other rivers throughout the region. Long-term reference tags revealed high variability in detection range, influenced primarily by line-of-sight, water depth, and discharge. Viewshed analyses were also employed to quantify detection range and may be a cost-effective alternative to formal range testing in systems where line-of-sight limits detection. A total of 80 Pallid Sturgeon were detected through active and passive telemetry between 2022-2023, including sub-adults, reproductive adults, and non-reproductive adults. Space use models were created for 72 adults and 6 sub-adults. Pallid Sturgeon detected within the lower Platte River during this study displayed higher residency in the Platte River in comparison to the Missouri River and movements occurred predominately at night. Further, adult Pallid Sturgeon exhibited greater space use areas compared to sub-adults. Distinct migration strategies were documented, including one-step and two-step migrations, with overwintering likely occurring throughout the lower Platte River basin. Results confirmed that, despite the low performance of acoustic telemetry in shallow, sand-braided rivers, species-specific designs can yield valuable movement information. The study emphasized that the lower Platte River basin may provide important resources for the conservation of multiple life-stages of Pallid Sturgeon.
Advisors: Mark A. Pegg and Jonathan J. Spurgeon
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Comments
Copyright 2024, Christopher F. Pullano. Used by permission