Genetic variation of resistance to mercury poisoning in steelhead (Oncorhynchus mykiss) alevins.
Newly hatched steelhead alevins were obtained from the factorial breeding of 24 male and 10 female steelhead trout, Oncorhynchus mykiss. Each set of offspring were in a separate cell. They were tested for resistance to intoxication by methylmercuric chloride (CH3HgCl) in water at a nearly constant mercury concentration of 8 microg l(-1). High mortality (81% of the tested alevins) occurred within 2 weeks. Resistance to intoxication, as measured by the time to death, as well as by the survival rate, shared high paternal and maternal variation with negligible interaction. Heritability of time to death was 0.59 +/- 0.17; heritability of survival (all-or-none trait) was lower (0.26 +/- 0.09). Mercury in dead alevins increased with time to death, exhibiting a large environmental variation and (comparatively) negligible genetic influence. At the end of the bioassay, the mercury content in survivors varied widely (3-21 microg g(-1) wet weight). The content was greater than, but correlated with that of dead alevins from the same cells, and it showed little relation with survival rate. Thus, it seems that resistance to poisoning implies a tolerance to high levels of mercury rather than a limitation of its accumulation.
Blanc
J M
JM
INRA, Unité de Recherche en Hydrobiologie, BP 3, 64310 Saint-Pée-sur-Nivelle, France. jmb@st-pee.inra.fr
McIntyre
J D
JD
Simon
R C
RC
D000818:Animals; D001681:Biological Assay; D005260:Female; D014644:Genetic Variation; D008297:Male; D008630:Mercury Poisoning / Q000235:genetics*; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000276:immunology*; D012044:Regression Analysis; D015996:Survival Rate; D014874:Water Pollutants, Chemical / Q000633:toxicity
D014874:Water Pollutants, Chemical