Masters Theses

Date of Award

12-1979

Degree Type

Thesis

Degree Name

Master of Science

Major

Ecology and Evolutionary Biology

Major Professor

David A. Etnier

Committee Members

Gordon M. Bughardt, M. C. Whiteside

Abstract

The life history, behavior, and ecology of Etheostoma sagitta (Jordan and Swain) were studied in the Cumberland River system in Tennessee. Diving equipment was utilized in making observations on macrohabitat, microhabitat, distribution, seasonal and diurnal activity, feeding behavior, migration, territoriality, associated species, competition, and population density and structure. Courtship, reproductive behavior, and diurnal activity were studied primarily in an experimental raceway. Feeding behavior and territoriality were studied in the raceway and in a 77.5-1. (20-gal.) aquarium. Parasites, longevity, age and growth, ova numbers and maturation, sex ratios, and food habitats were examined in the laboratory.

Etheostoma sagitta was found in clear as well as turbid streams. Habitats ranged from intermittent pools to small rivers. It more frequently occurred in streams with small rubble bottoms, but microhabitat varied with size class and season. Adults more frequently inhabited mid-channel portion of the stream while juveniles inhabited the periphery during the fall, winter, and spring. Migration was only noted in No Business Creek. Associated species and competition are discussed, with special reference to other Etheostoma.

Quantitative diurnal activity studies indicated that activity peaked in late morning (1100 hrs.) and probably ceased by 1900 hrs. Large males and females were more active than smaller fish.

Juvenile fish fed mainly upon copepods, cladocerans, and dipteran larvae. E. sagitta is sexually dimorphic. Males reached the height of coloration in spring. The color patter was retained throughout the year in adults but intensity faded after the breeding season. Females were only slightly brighter in the spring. Courtship and reproductive behavior began with construction of of a gravel depression by an adult male. During this activity, territorial behavior was centered upon the gravel nest area. This was the only time that territorial behavior was observed.

E. sagitta attains its greatest growth increment during the first year. Over the period of study, population densities did not change drastically; longevity was 4 years. A sex ratio of 1.04 males per females was observed.

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