Natural Resources, School of

 

First Advisor

Jonathan J. Spurgeon

Date of this Version

7-2024

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of the requirements for the degree of Master of Science

Major: Natural Resource Sciences

Under the supervision of Professor Jonathan J. Spurgeon

Lincoln, Nebraska, July 2024

Comments

Copyright 2024, Blake W. Logan. Used by permission

Abstract

Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis, collectively referred to as bigheaded carp, are invasive species in the United States of America that have expanded their range throughout the Missouri River basin in the last three decades. It may be desirable to develop management plans directed at the monitoring, control, or removal of bigheaded carp within the Missouri River basin. However, a knowledge gap exists regarding bigheaded carp ecology in Missouri River tributaries, which may be important for the development of management plans. As such, this study characterized bigheaded carp population demographics, occupancy, and connectivity in the Lower Platte River Basin (LPRB), which may serve as a suitable model for other relatively free-flowing streams in the Great Plains. Over 1,500 bigheaded carp were collected during the spring, summer, and fall of 2022 and 2023. Silver Carp were generally more abundant (n = 1,528) than Bighead Carp (n = 50) throughout the LPRB. Silver Carp population demographics were typical of an establishing population and were characterized by rapid individual growth and skewed sex ratios. Broad-scale variation in population demographics was suggestive of density-dependent processes, while fine-scale variation suggested other processes influence bigheaded carp demographics within the LPRB. Bigheaded carp occurred throughout the study area and detection probabilities were low near an invasion front. Genomic and microchemistry analyses were suggestive of high connectivity throughout the LPRB. This study provided insight into bigheaded carp population demographics, occupancy, and connectivity in the LPRB and may provide useful information for the development of bigheaded carp management plans in similar Great Plains streams.

Advisor: Jonathan J. Spurgeon

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