Relationship between water and otolith elemental concentrations in juvenile black bream Acanthopagrus butcheri

Abstract

Elements contained within calcified structures of fish, molluscs, bivalves and corals may provide a means to determine the characteristics of the environment occupied by an organism over time. In order to establish these characteristics it is first important to establish a link between one or more environmental variables and the concentration of elements within such a calcified structure. Black bream Acanthopagrus butcheri (Family: Sparidae) were reared for 30 d in the laboratory under controlled conditions, during which time the rearing water was spiked with different concentrations of strontium, barium and manganese. The Sr:Ca and Ba:Ca concentration ratios in the otoliths were related to water chemistry, while that of the Mn:Ca ratio was not. Furthermore the Sr:Ca concentration ratio in the rearing water was beyond levels previously examined. Mean partition coefficients (DMe) were calculated for Sr:Ca, Ba:Ca and Mn:Ca ratios, and were 0.131, 0.099 and 0.683 respectively. The relationship between the partition coefficients from each treatment group and the elemental ratio of the rearing waters was non-linear for all elements, suggesting that extrapolation of the data beyond the concentrations used is not justified. These results indicate that it is possible to reconstruct the past environmental characteristics from fish otolith chemistry, based on the concentration of elements in water. Establishing this link allows for the reconstruction of past environments that fish have occupied based on elemental chemistry.