SREL Reprint #2114

Responses of eastern mosquitofish (Gambusia holbrooki) to acute salinity stress: do family effects obscure inbreeding and genotype effects?

Karen L. Kandl1,2 and Andrew J. Thompson1

1Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA
2Department of Zoology and Institute of Ecology, University of Georgia, Athens, GA 30602, USA

Abstract: Eastern mosquitofish (Gambusia holbrooki) having inbreeding coefficients of 0, 0.125, and 0.25 were exposed to a salinity stress of 14.34 parts per thousand (ppt) for 96 hours, and their survival times were determined. Statistical models were fitted to the failure-time data to assess differences between the survival functions based on inbreeding coefficient, family, and genotype of the fish. Predicted median survival times were determined for inbreeding classes, families within inbreeding classes, classes heterozygosity classes, and genotypes of single loci. Family significantly affected survival of individuals in all analyses, reagardless of the inbreeding coefficient of the individual. Inbreeding coefficient of an individual did not statistically affect survival. Number of heterozygous loci per individual significantly affected survival time, but only when family as well as number of heterozygous loci per individual were considered as variables in the analysis. Genotypes of two loci, m-isocitrate dehydrogenase-A and glucose phosphate isomerase-B were also significantly correlated with survival. Our study demonstrates that family can account for a greater proportion of the variance in survival under environmental stress than either inbreeding coefficient or number of heterozygous loci. Family effects, in addition to inbreeding, should be considered in conservation management plans.

SREL Reprint #2114

Kandl, K.L. and A.J. Thompson. 1996. Responses of eastern mosquitofish (Gambusia holbrooki) to acute salinity stress: do family effects obscure inbreeding and genotype effects? Canadian Journal of Fisheries and Aquatic Sciences 53:753-760.

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