Meeting Abstract
Metal contamination of aquatic habitats can pose long-lasting effects that hinder the fitness of aquatic organisms. Top predatory fish are more prone to metal bioaccumulation than animals lower on the food web. Spotted gar (Lepisosteus oculatus) collected from Felsenthal Reservoir NWR in southern Arkansas displayed high concentrations of mercury (Hg) and selenium (Se) in muscle and liver (up to 70 ppm). In association, otolith (ossified structure of the inner ear) ring counting was used to age the collected fish. This study asks if those otoliths also provide a marker for metal exposure across the fish lifespan and if those metals measured in the otoliths correlate with tissue metal concentrations at the time of fish collection. We employed radioisotope X-ray fluorescence (XRF) to analyze the elemental spectra of otoliths and compared these microchemistry spectra to those measured in muscle and liver tissues of the respective fish. Here we present the correlations and discuss how otolith metal bioaccumulation may serve as a measure of life-long exposures. Further, we explore if finer resolution analysis (tighter beam diameter) of individual otolith ring elemental spectra may yield high-resolution data of the variation in lifetime exposures.
