Date of Award


Degree Name

Biological Sciences


College of Science

Type of Degree


Document Type


First Advisor

Donald Tarter

Second Advisor

Leonard J. Deutsch


Fish populations in the Ohio River have been monitored extensively by the Ohio River Valley Water Sanitation Commission (ORSANCO), along with state and Federal agencies, for over 40 years. The population data, collected via lock chamber rotenone surveys, showed that many species of Ohio River fish have demonstrated marked increases in abundance since these studies began. These trends in population density, both gradual and sharp, are likely associated with water quality improvements and the construction of high-lift dams. Pearson-r correlation through linear regression analyses showed 23 species or 42% of populations examined exhibit significant density increases from 1957 to 1998. An additional 27 species or 49% of those examined show distinct peaks in abundance by way of polynomial regression analyses. These trends were further revealed when population data was separated into three river sections (upper, middle, and lower). In all, 25 species or 89% demonstrated a significant density increase in one or more of the river sections. Such gradual increases in density are possibly related to improvements in water quality. These trends closely parallel changes induced by the Clean Water Act, 1972, which strengthened the control of waters discharged into the river. Also, 27 species or 100% were found to have undergone a significant peak in density in one or more of the river sections during the period of data collection. These “spikes” in fish density mirror increases in resource availability as high-lift dams expanded the water in the river channel. Percent family composition of groups showing both gradual density increases and density peaks were dominated by sunfishes (family Centrarchidae), minnows (family Cyprinidae), catfishes (family Ictaluridae), and suckers (family Catostomidae)—populations which may respond quickly to such habitat changes and reflect a more favorable environment.


Fish populations – Ohio River – Measurements.

Fish populations – Effect of water quality on.

Water quality management – Ohio River.