Department Chair

Alexander Y. Karatayev

Date of Award


Access Control

Open Access

Degree Name

Great Lakes Ecosystem Science


Great Lakes Center


Dimitry Gorsky, Ph.D.

Department Home page

First Reader

Lyubov Burlakova, Ph.D.

Second Reader

Knut Mehler, Ph.D.

Third Reader

Christopher Pennuto, Ph.D.


Lake sturgeon Acipenser fulvescens were once widely distributed throughout the Laurentian Great Lakes. However, widespread overharvest and habitat degradation has diminished their numbers. The lower Niagara River, NY contains one of the few remaining recovering populations of lake sturgeon in New York State. The goal of this study was to characterize the trophic position of lake sturgeon in the context of an invasive species dominated food web and to describe their movement patterns and residency within the lower Niagara River. Stomach content analysis and stable nitrogen (δ15N) and carbon (δ13C) isotope analysis of tissue was used to quantify trophic position. Acoustic telemetry was used to assess movement and residency. Sampled lake sturgeon exhibited a high degree of piscivory not seen in other Great Lakes’ populations. Stomach content and stable isotope analysis showed that sturgeon diet primarily consisted of invasive species, particularly the invasive round goby Neogobius melanostomus. Stable isotope analysis revealed that long-term average diet was dominantly round goby but short-term diet contained a varied group of benthic macroinvertebrates. Tracked lake sturgeon showed seasonal river residency, with most fish entering in the spring, staying through the summer, and then leaving for Lake Ontario in the winter. Tagged individuals congregated in the highest numbers just outside the mouth of the river in the summer and fall. The findings of this study are valuable to management plans that seek to protect this recovering population.