Author ORCID Identifier

https://orcid.org/0009-0002-9477-755X

Semester

Summer

Date of Graduation

2026

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Wildlife and Fisheries Resources

Committee Chair

Brent A. Murry

Committee Member

Caroline C. Arantes

Committee Member

Christopher Rota

Committee Member

Laura Gigliotti

Abstract

The introduction of aquatic invasive species is one of the greatest threats to freshwater biodiversity around the world. Two species of invasive carp, bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix) have spread throughout much of the Mississippi River Basin, resulting in serious ecological impacts to native communities. Their spread in the Ohio River, a major tributary of the Mississippi River, appears to have slowed, with limited evidence of upstream advancements. Here, we investigated abiotic and biotic factors that may be contributing to the reduced spread of invasive carp in the Ohio River Basin. Generally, bighead carp appear to occur in low abundances, with limited spawning and recruitment success, suggesting that they may not be well established in this basin. Silver carp, on the other hand, occur and persist throughout a large range of the mainstem Ohio River as well as in several major tributaries. However, the Ohio River appears to lack widespread suitable nursery habitat that would otherwise promote substantial population growth and continued spread. Consistent silver carp recruitment was only observed in a single location, Hovey Lake in JT Myers pool, which likely represents a major source population in Ohio River mainstem. We saw limited evidence that biotic interactions are contributing to the decreased success of silver carp in this basin. At their current densities, silver carp are likely coexisting with native species, despite substantial niche overlap. Consequently, recruitment failure appears to be the primary demographic bottleneck limiting the spread of silver carp in the Ohio River. Future management efforts should focus on expanded removal efforts in downstream pools. Such removal efforts could aid in ongoing management activities and target source populations that may be disproportionally contributing to silver carp recruitment in this basin.

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