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EVALUATION OF A NON-LETHAL SAMPLING TECHNIQUE FOR THE MEASUREMENT OF MERCURY (HG) CONCENTRATIONS AND STABLE-NITROGEN (15N/14N) ISOTOPE RATIOS IN LARGE MOUTH BASS (MICROPTERUS SALMOIDES)
Citation:
Ryba, S AND J L. Lake. EVALUATION OF A NON-LETHAL SAMPLING TECHNIQUE FOR THE MEASUREMENT OF MERCURY (HG) CONCENTRATIONS AND STABLE-NITROGEN (15N/14N) ISOTOPE RATIOS IN LARGE MOUTH BASS (MICROPTERUS SALMOIDES). Presented at 11th Annual Conference of the Wildlife Society, Calgary, Alberta, Canada, September 18-22, 2004.
Description:
Contaminant bioaccumulation studies often rely on fish muscle filets as the tissue of choice for the measurement of nitrogen stable isotope ratios ( 15N) and mercury (Hg). Lethal sampling techniques may not be suitable for studies on limited populations from smaller sized aquatic systems. The development of non-lethal techniques to predict Hg levels and 15N in muscle tissue from scale samples would offer researchers the capability to repeatedly sample fish without impacting community size. In addition, scale sampling and analysis would allow researchers to acquire data from angling tournaments, as well as 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.