Publication Date


Document Type


First Advisor

Mathers, Carrol K.||Feyerherm, Harvey A.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences


Darters (Fishes); Fishes


The habitat of the Orangethroat darter, Etheostoma spectablle (Agassiz), is the shallow, rock or gravel bottomed riffle areas of smaller streams. Laboratory studies were conducted to ascertain the dissolved oxygen requirements of this fish. The Orangethroat darter inhabits pool and riffle areas of the O'Neil Branch Creek in Northern Illinois. From measurements of the physico-chemical environments for these two areas, dissolved oxygen concentrations were found to range from 12.5 ppm in the riffle to 7.3 ppm in the pool. The field study served as a guideline for a series of laboratory tests to determine the effects of varying temperatures (10-12° C and 20.5-21.5° C) and dissolved oxygen concentrations on activities of adult male, female, and Juvenile Orangethroat darters. Darters were acclimated for temperature and diminishing amounts of dissolved oxygen for a 24 hour period prior to each test. Measurements of opercular movements, oxygen consumption, and levels of asphyxiation were taken while the fish were in individual testing chambers. Results of this laboratory phase were: 1. Opercular movements in relation to oxygen concentration were inconsistent and erratic. 2. Individual tests of the two series, at both the higher and the lower levels of oxygen concentrations, showed no consistent Indirect relations between oxygen consumption and decreased oxygen concentrations. 3. Oxygen concentrations of 1.0-1.8 ppm were fatal to all Orangethroat darters while they were functioning at or near standard metabolism.


Includes bibliographical references.||Includes illustrations and maps.


x, 46 pages




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