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Effects of injected methylmercury on the hatching of common loon (Gavia immer) eggs

Kenow, K.P., Meyer, M.W., Rossmann, R., Grendron-Fitzpatrick, A. and Gray, B.R., 2011, Effects of injected methylmercury on the hatching of common loon (Gavia immer) eggs: Ecotoxicology, v. 20, n. 7, p.1684-1693. (DOI: 10.1007/s10646-011-0743-9)

Abstract

To determine the level of in ovo methylmercury (MeHg) exposure that results in detrimental effects on fitness and survival of loon embryos and hatched chicks, we conducted a field study in which we injected eggs with various doses of MeHg on day 4 of incubation. Eggs were collected following about 23 days of natural incubation and artificially incubated to observe hatching. Reduced embryo survival was evident in eggs injected at a rate of ≥1.3 μg Hg/g wet-mass. When maternally deposited Hg and injected Hg were considered together, the median lethal concentration of Hg (LC50) was estimated to be 1.78 μg Hg/g wet-mass. Organ mass patterns from eggs of chicks injected at a rate of 2.9 μg Hg/g differed from that of controls and chicks from the 0.5 μg Hg/g treatment, largely related to a negative relation between yolk sac mass and egg mercury concentration. Chicks from eggs in the 2.9 μg Hg/g treatment were also less responsive to a frightening stimulus than controls and chicks from the 0.5 μg Hg/g treatment. We also found that the length of incubation period increased with increasing egg mercury concentration. Tissue Hg concentrations were strongly associated (r 2 ≥ 0.80) with egg Hg concentration.

Keywords

common loon, (Gavia immer)