Tara L. Rose

Date of Award

1999

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Dr. Donald Tarter

Second Advisor

Leaonard J. Deutsch

Abstract

The family Catostomidae represents a major component of the fish fauna in the Ohio River. Because of their abundance, large biomass, and susceptibility to environmentally-induced anomalies, suckers are expected to significantly influence the Ohio River Fish Index (ORFIn), a biological index being developed by the Ohio River Valley Water Sanitation Commission (ORSANCO) for large river systems. To correctly interpret information obtained from ORFIn, the impact of suckers upon the index must be thoroughly understood, including relative importance and uneven spatial distribution of Ohio River suckers. In this study, suckers represented 7.1 percent of the total fish captured and 36.6 percent of the biomass taken during boat electrofishing collections between 1991 and 1998. Round-bodied and deep-bodied suckers were approximately equal in abundance; however, deep-bodied suckers contributed a greater proportion of the total biomass than did round-bodied suckers. All species of sucker studied showed longitudinal spatial distribution significantly different from expected riverwide distribution. All round-bodied suckers and three deep-bodied suckers were found in greatest numbers in the upper Ohio River, while the three remaining deep-bodied species were more abundant in the lower river. Longitudinal changes in spawning stream availability, food habits, and substrate composition were primary influences on the distribution of Ohio River suckers. The extreme lower river was relatively lacking in available spawning streams. Deep-bodied suckers showed increasingly generalist food habits in the lower river, resulting in an extended range over the round-bodied suckers of the upper river. Coarse substrates and higher gradients in the upper river represented optimal sucker habitat. Round-bodied suckers showed a slightly greater abundance in the upper sections of navigational pools than in the lower sections, most likely the result of changes in substrate and gradient. Suckers have increased significantly in abundance during the last 40 years, particularly in the last 20 years. This increase appears to have resulted from improved water quality brought about by clean water legislation in the early 1970s. Although suckers increased in number throughout the entire river, the increase was greatest in the upper one-third of the river, where water quality was exceptionally poor at the beginning of the study period.

Subject(s)

Catostomidae – Ohio River.

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