Long term trends of Hg uptake in resident fish from a polluted estuary

• Published in: Marine pollution bulletin Vol. 73; no. 1; pp. 263 - 272
• Main Authors: Jones, Hugh J., Swadling, Kerrie M., Tracey, Sean R., Macleod, Catriona K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15-08-2013; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Biometric modelling; biometry; Brackish; Brackish water ecosystems; Ecotoxicology, biological effects of pollution; Environmental Monitoring; Estuaries; Estuarine management; fish; Fishes - metabolism; Food Chain; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Long term monitoring; Marine; Marine and brackish environment; mathematical models; mercury; Mercury - metabolism; Mercury bioaccumulation; Methods and techniques (sampling, tagging, trapping, modelling...); monitoring; Platycephalus bassensis; Sea water ecosystems; spatial variation; Synecology; Von Bertalanffy growth curves; Water Pollutants, Chemical - metabolism; water pollution; Water Pollution, Chemical - statistics & numerical data; Von Bertalanffy growth curves; Mercury bioaccumulation; Biometric modelling; Long term monitoring; Estuarine management; Biometrics; Brackish water environment; Growth; Estuaries; Long term; Modeling; Von Bertalanffy model; Uptake; Marine environment; Pollution; Resident; Biological accumulation; Mercury
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2013.04.032

•Temporal models of Hg concentrations in estuarine fish over 37-years examined.•Models showed no temporal decline in fish Hg levels despite reduction of Hg inputs.•Interannual variation in Hg accounted for by fish length and growth rate variation.•Results highlight importance of biometric parameters in Hg monitoring programs.
Mercury contamination of fish is dependent upon a system’s ability to transform inorganic Hg into biologically available forms; however, fish biometrics also play an important role. To assess long term trends in Hg concentrations in sand flathead (Platycephalus bassensis) a polynomial model, corrected for fish length, was used to evaluate temporal trends and spatial variability, while growth rates were estimated using the Von Bertalanffy length-at-age model. Hg concentrations showed no decrease over time, and generally remained near recommended consumption levels (0.5mgkg−1). Previously reported spatial differences in Hg concentrations were not supported by the data once the models were corrected for fish length. Growth rate variation accounted for a large part of the previously published spatial differences. These results suggest that inclusion of fish biometrics is necessary to facilitate an accurate interpretation of spatial and temporal trends of contaminant concentrations in long term estuarine and marine monitoring programs.