SREL Reprint #2519

Effect of mercury and Gpi-2 genotype on standard metabolic rate of eastern mosquitofish (Gambusia holbrooki)

Christopher Paul Tatara1, Michael C. Newman2, and Margaret Mulvey2

1National Marine Fisheries Service, Southwest Region, 777 Sonoma Avenue, Suite 325,
Santa Rosa, California 95404, USA
2The College of William and Mary, Virginia Institute of Marine Science, School of Marine Science,
Gloucester Point, Virginia 23062-1346, USA

Abstract: Previous studies demonstrated differential mortality among mosquitofish of different Gpi-2 genotypes during acute mercury and arsenate exposures. Mercury-exposed mosquitofish also had Gpi-2 genotype-specific differences in glycolytic and Krebs cycle metabolite pools. The mortality and metabolite data suggested that mosquitofish bearing specific Gpi-2 genotypes might differ in metabolic efficiency, with less efficient Gpi-2 genotypes having higher standard metabolic rates (SMRs) and shorter times to death during acute mercury exposure. Effect of Gpi-2 genotype on SMR was assessed with a factorial arrangement of six Gpi-2 genotypes and two exposure sequences (Control — Control; Control — 100 µg/L Hg). The SMRs were estimated by measuring oxygen consumption using an indirect, closed-circuit, computer-controlled respirometer. A 48-h exposure to 100 µg/L of mercury resulted in a 16.7% elevation of SMR above control levels (p = 0.001). The Gpi-2 genotype and the number of heterozygous loci per individual had no significant effect on SMR in mercury-exposed mosquitofish. The experimental results do not support the hypothesis that Gpi-2 genotype-specific differences in glycolytic and Krebs cycle metabolite pools and mortality in mosquitofish exposed to mercury are associated with differences in SMR.

Keywords: Gambusia holbrooki, Standard metabolic rate, Genetics, Mercury

SREL Reprint #2519

Tatara, C. P., M. C. Newman, and M. Mulvey. 2001. Effect of mercury and Gpi-2 genotype on standard metabolic rate of eastern mosquitofish (Gambusia holbrooki). Environmental Toxicology and Chemistry 20: 782-786.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).