IDENTIFYING RECRUITMENT SOURCES OF SILVER CARP (Hypophthalmichthys molitrix) IN THE OHIO RIVER BASIN

Author

Mitchell Konieczny, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2025

Degree Name

Master of Science

Department

Zoology

First Advisor

Whitledge, Gregory

Abstract

Knowledge of invasive silver carp (Hypophthalmichthys molitrix) recruitment sourcesand habitat use during early life is important for informing efforts to limit recruitment and the placement of deterrents to inhibit further range expansion. However, low sampling efficiency can limit detection of age-0 fish during the early stages of an invasion. Capture records of young-of- year fish as far upriver as Markland Pool are indicative of continued upstream expansion of the carp reproductive front in the Ohio River, but relative importance of locations contributing to carp recruitment across the Ohio River basin are unknown. The goal of this study was to elucidate sources of silver carp recruitment in the Ohio River and better understand the extent of their reproductive front using otolith microchemistry. Silver carp were collected from the Ohio River utilizing electrofishing during 2021 and 2022. Water chemistry data from 2006-2023 sampling was used to facilitate interpretation of otolith microchemistry data. Results indicate that multiple recruitment sources are supporting upstream expansion of Silver Carp in the Ohio River, tributaries are frequently used during early life stages, and that dispersal among tributaries and different sections of the Ohio River appears to be common. Results also indicate that reproduction is occurring in areas upstream of Markland Pool where early life stages have not yet been observed. The results of this research will help inform management agencies on the current status of the silver carp invasion in the Ohio River basin and assist in the implementation of control efforts to help slow their continued establishment and invasion.