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Assessment of Caudal Fin Clips as a Non-lethal Technique for Predicting Muscle Tissue Mercury Concentrations in Largeouth Bass
Citation:
RYBA, S. A., J. L. LAKE, J. R. SERBST, A. D. Libby, AND S. AYVAZIAN. Assessment of Caudal Fin Clips as a Non-lethal Technique for Predicting Muscle Tissue Mercury Concentrations in Largeouth Bass. ENVIRONMENTAL CHEMISTRY. CSIRO Publishing, Collingwood Victoria, Australia, 5(3):200-203, (2008).
Impact/Purpose:
This study examined the relationship between total mercury (Hg) concentration in caudal fin clips scales and in tissues of largemouth bass (Micropterus salmoides) from freshwater sites to determine whether fin clip analysis would allow a non-lethal and convenient method for predicting mercury concentrations in tissues. Mercury contamination has resulted in advisories suggesting limiting or eliminating consumption of fish at sites in 45 states and 19 states have issued statewide advisories for mercury in freshwater lakes and/or rivers. The risks of increased Hg concentrations in the diets of wildlife are also a major concern when measured concentrations of Hg in some fish exceed the levels deemed to be safe for some piscivorous wildlife. Non-lethal techniques offer researchers the ability to gather larger sample sizes, investigate rare species and perform multiple samplings of fish with little impact on population sizes. Likewise this innovative approach of analyzing fin clips would facilitate the collection of samples from angling tournaments and fish surveys. The investigation of caudal fin clips as a muscle tissue surrogate in the current study is attractive because this technique is a commonly used by fisheries biologists in mark and recapture studies. This technique can allow samples to be obtained with only minimal impact on the fish. Fin clip analysis appears to be useful for assessing general trends in contamination for comparison of levels from different geographical areas, and as a first level screen for assessing Hg contamination at sites
Description:
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. The Hg concentration in fin clip samples (mean = 0.261 ug/g (dry)) was more than a factor of twenty greater than in the scale samples (mean = 0.012 ug/g (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.