Murray State Theses and Dissertations

Abstract

Invasive species continue to threaten aquatic ecosystems in the United States. Silver Carp Hypophthalmichthys molitrix have successfully infiltrated much of the Mississippi River Basin, including Kentucky Lake – a large reservoir located on the Tennessee River in Western Kentucky. Although Silver Carp have been present in Kentucky Lake for at least a decade, until recently, very little was known about the population, how often successful reproduction is occurring, or the environmental conditions that facilitate strong year-classes. Hence, it is difficult for managers to predict the potential impact of Silver Carp on native species. Silver Carp were collected from Kentucky Lake using gill nets, cast nets/anglers, boat electrofishing, and commercial fishing. Population demographics (size, age, growth, condition, and mortality) of Silver Carp within Kentucky Lake were examined by measuring total length and weight for all fish and removing a pectoral fin ray for aging. Additionally, spawning periodicity of mature Silver Carp in Kentucky Lake was examined by calculating gonadosomatic index (GSI) or the weight of the gonads relative to the fish’s body weight each month for just over a year. Fecundity (number of eggs per female) was estimated by multiplying the average number of eggs within six 1-g sub-samples by the combined weight of both ovaries. Silver Carp in Kentucky Lake were larger sized, faster growing, relatively heavy, and comparatively unexploited compared to other populations in the United States. Female Silver Carp in Kentucky Lake also exhibited higher fecundity than Silver Carp from other populations in the United States. Silver Carp appear to spawn in mid-spring in conjunction with warming water temperatures and rising water flows similar to other populations. Additionally, the capture of young-of-the-year Silver Carp suggests that successful natural reproduction is occurring in Kentucky Lake. These data provide a snapshot of a relatively recent invasion of Silver Carp and are among the first to characterize reproduction in a large mesotrophic reservoir. Therefore, the results of this study may serve as a model for other large mesotrophic systems such as the embayments of the Great Lakes.

Year manuscript completed

2020

Year degree awarded

2020

Author's Keywords

Silver Carp, population dynamics, Kentucky Lake, age, growth, invasive species

Thesis Advisor

Timothy Spier

Committee Member

Michael Flinn

Committee Member

Howard Whiteman

Committee Member

Kate He

Committee Member

Gary Stinchcomb

Document Type

Thesis

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