Elemental composition of fish otoliths and contaminant levels along an estuarine pollution gradient

The chemical composition of fish otoliths is receiving increasing attention as a potential indicator or fingerprint of the chemical composition of fish habitats. Central to this is the hypothesis that a temporal record of elemental chemistry of resident waters is permanently recorded in the radially accreting layers of the otolith. The validity of this hypothesis was investigated by sampling fish (young-of-the-year Atlantic croaker, (Micropogonias undulatus) at discrete stations along a 50 km longitudinal transect in a heavily industrialized estuary (Galveston Bay, USA). Elemental composition of whole otoliths was determined by inductively coupled plasma mass spectrometry. Liver tissue and bottom sediment data were available for both elemental and organic contaminants at the same sampling stations