Environmental context. In the development of fish consumption advisories, fisheries biologists routinely sacrifice fish and analyse muscle fillets in order to determine the extent of mercury contamination. Such lethal techniques may not be suitable for endangered species or limited fish populations from smaller-sized water bodies. We compared the measured total mercury concentrations in tail fin clips to that of muscle fillets and illustrated that tail fin clips may be used as an accurate tool for predicting mercury in muscle tissue. This is the first study on the use of tail fin clips to predict mercury levels in the muscle tissue of largemouth bass with minimal impact on the fish.

Abstract. The statistical relationship between total mercury (Hg) concentration in clips from the caudal fin and muscle tissue of largemouth bass (Micropterus salmoides) from 26 freshwater sites in Rhode Island, USA was developed and evaluated to determine the utility of fin clip analysis as a non-lethal and convenient method for predicting mercury concentrations in tissues. The relationship of total Hg concentrations in fin clips and muscle tissue showed an r² of 0.85 and may be compared with an r² of 0.89 for Hg concentrations between scales and muscle tissue that was determined in a previous study on largemouth bass. The Hg concentration in fin clip samples (mean = 0.261 μg g^–1 (dry)) was more than a factor of twenty greater than in the scale samples (mean = 0.012 μg g^–1 (dry)). Therefore, fin clips may be a more responsive non-lethal predictor of muscle-Hg concentrations than scale in fish species which may have reduced Hg concentrations.