Department Chair

Alexander Y. Karatayev

Date of Award


Access Control

Open Access

Degree Name

Great Lakes Ecosystem Science


Great Lakes Center


Alicia Pérez-Fuentetaja, Ph.D., Professor of Biology

Department Home page

First Reader

Alicia Pérez-Fuentetaja, Ph.D., Professor of Biology

Second Reader

Gary W. Pettibone, Ph.D., Professor of Biology

Third Reader

Randal J. Snyder, Ph.D., Professor of Biology


Using fishes as bioindicator species can be an effective method for detecting poor water quality in aquatic ecosystems. In the Niagara River, the emerald shiner (Notropis atherinoides) is a keystone species that is sensitive to ecosystem degradation and, therefore, fills the bioindicator role. Like other model bioindicators, emerald shiners are abundant and, when exposed to a persistent disturbance, exhibit individual signs of stress before the onset of population decline. This research evaluated the health of emerald shiners captured from the upper Niagara River, which is at times inundated with untreated sewage from combined sewer overflows (CSOs). Water samples were taken biweekly from seven sites in the upper Niagara River and one site in Lake Erie, to determine Escherichia coli’s most probable number (MPN)/100 mL from May-October 2016. Emerald shiners were captured from riverine sites and given an overall health score using the Health Assessment Index (HAI), which incorporates nine physiological parameters, plus their condition factor and liver bacterial infection. Most water samples were below the Environmental Protection Agency criteria for E. coli MPN in a class A stream. However, 35% of fish were positive for internal liver infection. Fulton’s condition factor for emerald shiners reflected measured signs of severe stress such as hemorrhaging and high parasite loads. The most stressed fish were captured in the eastern branch of the river, which is highly urbanized and includes the cities of Buffalo, NY and Tonawanda, NY which produce high CSO effluent. In comparison, the emeralds shiners in the western branch of the river, which is less developed along both the USA and Canadian shorelines, had overall better health markers. These results provide supporting evidence that emerald shiners are exhibiting immunological stress and current water pollution levels are stressing the shiner population in the river, despite compliance with EPA regulations for E. coli input. The future of this keystone species and the health of the ecosystem hinge on solving the issue of the excessive anthropogenic contamination in the Niagara River.