Mercury bioaccumulation in an estuarine predator: Biotic factors, abiotic factors, and assessments of fish health

• Published in: Environmental pollution (1987) Vol. 214; pp. 169 - 176
• Main Authors: Smylie, Meredith S., McDonough, Christopher J., Reed, Lou Ann, Shervette, Virginia R.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2016
• Subjects: Animals; Brackish; Ecosystem; Environmental Monitoring - methods; Female; Fishes; Lepisosteus osseus; Longnose gar; Male; Mercury - analysis; Methylmercury; Methylmercury Compounds - analysis; Seasons; Trophic ecology; Water Pollutants, Chemical - analysis; Wetlands; USA; Longnose gar; Trophic ecology; Lepisosteus osseus; Methylmercury
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2016.04.007

Estuarine wetlands are major contributors to mercury (Hg) transformation into its more toxic form, methylmercury (MeHg). Although these complex habitats are important, estuarine Hg bioaccumulation is not well understood. The longnose gar Lepisosteus osseus (L. 1758), an estuarine predator in the eastern United States, was selected to examine Hg processes due to its abundance, estuarine residence, and top predator status. This study examined variability in Hg concentrations within longnose gar muscle tissue spatially and temporally, the influence of biological factors, potential maternal transfer, and potential negative health effects on these fish. Smaller, immature fish had the highest Hg concentrations and were predominantly located in low salinity waters. Sex and diet were also important factors and Hg levels peaked in the spring. Although maternal transfer occurred in small amounts, the potential negative health effects to young gar remain unknown. Fish health as measured by fecundity and growth rate appeared to be relatively unaffected by Hg at concentrations in the present study (less than 1.3 ppm wet weight). The analysis of biotic and abiotic factors relative to tissue Hg concentrations in a single estuarine fish species provided valuable insight in Hg bioaccumulation, biomagnification, and elimination. Insights such as these can improve public health policy and environmental management decisions related to Hg pollution. [Display omitted] •Hg concentrations were highest in the smallest and youngest individuals.•Foodwebs and spatial use of estuaries were strong predictors of Hg levels.•An initial Hg loss with size in longnose gar was likely driven by maternal transfer.•Fecundity and growth rate were not hindered at concentrations in the present study. Foodweb ecology and spatial use patterns in variable environments such as estuaries can be strong determinants of Hg bioaccumulation in fishes.