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THE DEVELOPMENT OF A PREDICTIVE TOLL USING LARGEMOUTH BASS (MICROPTERUS SALMOIDES) SCALES TO ESTIMATE MERCURY (HG) CONCENTRATIONS AND STABLE-NITROGEN (15N/14N) ISOTOPE RATIOS IN FISH MUSCLE TISSUE
Citation:
Ryba, S AND J L. Lake. THE DEVELOPMENT OF A PREDICTIVE TOLL USING LARGEMOUTH BASS (MICROPTERUS SALMOIDES) SCALES TO ESTIMATE MERCURY (HG) CONCENTRATIONS AND STABLE-NITROGEN (15N/14N) ISOTOPE RATIOS IN FISH MUSCLE TISSUE. Presented at Southern New England Chapter of the American Fisheries Society, Old Lyme, CT, January 21, 2004.
Description:
Knowledge of the trophic structure of biota in aquatic sites offers potential for the construction of models to allow the prediction of contaminant bioaccumulation. Measurements of trophic position have been conducted using stable-nitrogen isotope ratios ( 15N) measured in fish muscle tissue, and this tissue is also often used for analysis of Hg in fish. The development of techniques to predict Hg levels and 15N in muscle tissue from scale samples would offer researchers the capability to acquire data from angling tournaments in a non-lethal manner as well as to develop historical trend data from archived fish scale collections. This study measured 15N values and Hg concentrations in scales and muscle tissues from largemouth bass (Micropterus salmoides) collected in Rhode Island from small freshwater sites which covered a range of nutrient enrichment and Hg fish concentrations. Nitrogen isotope values ( 15N) were measured in the scales and dorsal muscle tissue of 31 largemouth bass from 12 small freshwater sites, and these values ranged from 7.1 - 14.1 ? and 8.5 - 16.1 ? for scales and muscle, respectively. A significant linear relationship was observed between scale and muscle tissue 15N values (p<0.01; R2=0.91) Hg concentrations were measured in the scales and dorsal muscle tissue of 50 largemouth bass, and these values ranged from 0.0023 - 0.215 ug/g and 0.451 - 5.919 ug/g for scales and muscle, respectively. A significant linear relationship was observed between scale and muscle tissue Hg concentrations (p<0.01; R2=0.76). Overall these results demonstrate the potential for utilizing fish scales for supplying data on 15N and Hg concentrations in fish.