Agricultural Sciences and Natural Resources, College of (CASNR)

 

First Advisor

Mark A. Pegg

Committee Members

Jonathan Spurgeon, Rene Martin, Kirk Steffensen

Date of this Version

8-2024

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 Professor Mark A. Pegg

Lincoln, Nebraska, August 2024

Comments

Copyright 2024, Joshua F. Kocik. Used by permission

Abstract

Invasive Carp species: Silver Carp Hypophthalmichthys molitrix, Bighead Carp Hypophthalmichthys nobilis, Grass Carp Ctenopharyngodon idella, and Black Carp Mylopharyngodon piceus have both potential and realized abilities to negatively impact native species. Specifically, Bighead Carp and Silver Carp as filter feeders have been theorized to be detrimental not only to adult filter-feeding species, but to many fish which rely on plankton and algae in their early-life stages. The impact of Invasive Carp on the overall fish community remains underexplored. The fish communities below Gavins Point Dam (Invasive Carp present) and Fort Randall Dam (Invasive Carp absent) afford the opportunity to directly compare recent sampling with historic sampling done in these same reaches. This study set out to determine if there is a difference between the contemporary Gavins Point Dam and Fort Randall Dam fish communities, and whether that difference can be attributed to Invasive Carp presence. To account for many of the innate differences between the waters below Gavins Point Dam and Fort Randall Dam, historic data were incorporated with contemporary sampling efforts. While the differences in the fish communities below Gavins Point Dam and Fort Randall Dam could not be directly tied to Invasive Carp presence, decreased condition of Bigmouth Buffalo Ictiobus cyprinellus in the presence of Invasive Carp indicates that Bighead Carp and Silver Carp may be negatively impacting native species. This study also stands as a repeatable framework for sampling the fish communities below Gavins Point Dam and Fort Randall Dam should Invasive Carp get introduced above Gavins Point Dam or Black Carp be detected in the Gavins Point Dam tailrace. Another goal of this study was to define the population dynamics of Invasive Carp below Gavins Point Dam to make informed management recommendations. This study found no evidence of young-of-year and few age-1 Invasive Carp in the tailrace of Gavins Point Dam. This may allow a unique opportunity to implement barriers to Invasive Carp immigration to the tailrace, thereby decreasing their presence at the furthest upriver point of their invasion. Additionally, Silver Carp below Gavins Point Dam appear to be utilizing a “live-fast-die-young” adaptation, which allows for quicker growth rates with shorter lifespans. This strategy would suggest that removal, combined with preventative measures to limit immigration, has a chance to make a significant impact on this population of Invasive Carp in a relatively short amount of time.

Advisor: Mark A. Pegg

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