Volume 14, Issue 8 pp. 1411-1418
Article
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Genetic and demographic responses of mosquitofish (Gambusia holbrooki girard 1859) populations stressed by mercury

Margaret Mulvey

Corresponding Author

Margaret Mulvey

University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802

University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802Search for more papers by this author
Michael C. Newman

Michael C. Newman

University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802

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Ann Chazal

Ann Chazal

University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802

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M. Michele Keklak

M. Michele Keklak

University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802

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M. Gay Heagler

M. Gay Heagler

University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802

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L. Stan Hales Jr.

L. Stan Hales Jr.

Zoology Department, University of Georgia, Athens, Georgia 30602

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First published: August 1995
Citations: 22

Abstract

Genetic and demographic changes in mosquitofish populations are reported after chronic (111 d) exposure to mercury. Sex ratios, normally female-biased in field populations, were also female-biased in control mesocosms. However, the sex ratio was male-biased in the mercury treatments. Frequencies of glucosephosphate isomerase-2 (Gpi-2) allozymes for fish exposed to mercury differed from initial frequencies and from those of control fish. In a selection-component analysis, female sexual selection was statistically significant for the mercury-treated fish; the proportion of females that were gravid differed among Gpi-2 genotypes. The number of developing embryos per female also differed among Gpi-2 genotypes. Mercury had genotype-specific effects on mosquitofish reproduction in addition to genotype-specific effects on mortality reported earlier. These effects may reflect metabolic qualities of the Gpi-2 genotypes or loci closely linked to the Gpi-2 locus.

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