Distribution of mercury in the American alligator (Alligator mississippiensis), and mercury concentrations in the species across its range
Moore, Liberty Ann
MetadataShow full item record
American alligators (Alligator mississippiensis) are top-level predators that can accumulate mercury in high concentrations. As human consumption of alligator continues to increase, there is an increased public health concern. I conducted two studies examining mercury concentrations in the American alligator. The first study was conducted on alligators from the Rockefeller Wildlife Refuge (RWR), Louisiana, to determine how mercury is distributed among body organ/tissue compartments. Samples from body organ/tissue compartments, including brain, gonad, heart, kidney, liver, and muscle were tested for mercury (Hg) and stable isotope (?13C and ?15N) signatures. Relationships between body organ/tissue compartments and non-invasive samples (blood, claws and dermal tail scutes) were examined to determine whether concentrations in non-invasive samples could be used to monitor populations non-lethally. Mercury concentrations in all organ/tissue compartments were correlated with each other, body size, and ?15N signatures. The ?13C signatures were not correlated with mercury concentrations or body size. Mercury was highest in the blood, followed by kidney and liver. Concentrations of mercury were lowest in gonad and brain tissue. Because mercury concentrations from blood, claws, and scutes were correlated with those of the internal organs/tissue compartments, non-lethal sampling methods may be a viable method of indexing 2 mercury burdens in body tissues. The second study involved examining tail muscle and liver samples from wild alligators in Alabama, Georgia, South Carolina, and the Rockefeller Wildlife Refuge in Louisiana, and an alligator farm in Mitchell County, Georgia to determine if mercury concentrations varied geographically in the species. The highest Hg concentrations were found in alligators from Glynn County, Georgia and southeast Alabama, while the lowest were found in the alligators from the RWR and the alligator farm. Differences among locations suggested that alligators could be used as biomonitors of mercury in the locations they inhabit.