Date of Award

1997

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Leonard J. Deutsch

Second Advisor

Dr. Donald C. Tarter

Third Advisor

Maryetta Hight

Fourth Advisor

Thomas K. Pauley

Abstract

Prior to 1988, two subspecies of the mosquitofish Gambusia affinis (G. a. affinis and G. a. holbrooki) were recognized along the Gulf and Atlantic Coasts of the United States. Based on electrophoretic analysis, subsequent investigators recognized G. holbrooki and G. affinis as separate species. Populations in drainages west of Mobile Bay were considered G. affinis, and those east of this divide being G. holbrooki. The only mosquitofish population in West Virginia is found in the Meadow River wetlands (1392 ha). This wetland complex is located at the western end of Greenbrier County in the Allegheny Mountain Province. Heart, skeletal muscle, and brain tissues, malate dehydrogenase isozyme patterns, along with morphometric characteristics, (e.g. dorsal and fin rays, etc.), were used to determine that the West Virginia population was G. affinis. The average PI value for the West Virginia and Kentucky populations was 1.69 and the average PI value for the Virginia population was 2.19. Females from the Meadow River wetlands became sexually mature at 32 mm in length. The population of mosquitofish in the wetlands began its reproductive period on May 24 and ended between September 7 and September 29, which is a period of approximately 15 weeks. During this time, a total of 5 broods were liberated. The smallest mature male was 22 mm long (range 22-38 mm) and the smallest mature female was 32 mm long (range 32- 51 mm). The number of individuals in each brood was dependent on the total length of the female. The relationship between the total length of the female and the number of embryos was shown by the equation Y=-40.46+(2.009X) and r=0.648 which is significant at the 0.05 confidence limit. The percentage of females that were gravid throughout the summer was dependent on the water temperature (21-30°C).

Subject(s)

Eastern mosquitofish – Reproduction.

Western mosquitofish – Reproduction.

Gambusia – West Virginia.

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