Meeting Abstract
Mercury is a persistent, globally distributed contaminant that biomagnifies through food webs, causing mortality, reproductive failure and other health concerns in humans and wildlife. Songbirds in some polluted watershed areas have highly elevated blood mercury levels. The effects of mercury on fertility have primarily been examined through correlative field studies and the use of unrealistic doses or modes of mercury exposure under laboratory conditions. To investigate the effects of ecologically relevant levels of dietary mercury exposure on sperm quality and fertility, we presented captive zebra finches with a diet containing mercury at levels comparable to a highly polluted watershed and examined how sperm morphology and motility changed in mercury-exposed animals relative to controls. All birds were then paired with non-exposed females, and eggs were dissected to study whether the ability of the sperm to reach the perivitelline membrane in the egg was affected. Preliminary results suggest that testis size, sperm length and sperm counts were reduced in mercury dosed birds, and fewer sperm cells reached the egg. If exposure to ecological mercury levels reduces male fertility, mercury pollution could reduce the potential gene pool and population viability in regions affected by mercury pollution.
