| Summary: | 329-334 Concentrations of Ag, As, Cd, Cu, Fe, Hg, Mn, Pb, Se, and Zn in livers of Atlantic croaker (Micropogonias undulatus) increased with fish length in a collection of 47 fish from coastal North Carolina. This pattern of increase might be expected for contaminant metals such as Ag, Cd, Hg, and Pb which are poorly regulated and only slowly excreted, but it is uncommon for the biologically essential elements Cu, Fe, Mn, Se, and Zn which are under homeostatic control. Concentrations of copper in fish collected from sites in Galveston Bay, Texas are used to illustrate bias in estimating mean concentrations when such relationships exist. Adjustment for bias and reduction in variance estimates are made by analysis of covariance (ANCOVA), both of which can improve the power to detect spatial and temporal trends. Other biological covariates can partly explain observed metal variations in fish livers. Further improvements in reducing bias and variance are possible by their inclusion in ANCOVA adjustment, but the generality of such adjustments will depend on a better understanding of the mechanisms by which they exert their influence http://gbic.tamug.edu/request.htm
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