Effects of temperature and elemental concentration on the chemical composition of juvenile yellow perch (Perca flavescens) otoliths

Otolith microchemistry studies assume that a relationship exists between the concentration of trace elements in the environment and otolith chemical composition. Although this assumption has been tested using marine and estuarine fish in controlled laboratory experiments, the relationships among temperature, ambient elemental concentration, and otolith chemical composition for freshwater species is not well documented. Here, juvenile yellow perch (Perca flavescens) were reared under different concentrations of four elements (Ba, Mg, Mn, and Sr) crossed with three temperatures (10 degrees C, 15 degrees C, and 20 degrees C) to determine the interactive influence of ambient elemental concentrations and temperature on otolith chemical composition. Sr: Ca and Ba: Ca were significantly related to ambient elemental concentrations, but Mg: Ca and Mn: Ca were not. Although the relative influence of temperature was less than that of ambient elemental concentrations, Sr: Ca, Ba: Ca, and Mn: Ca were all influenced by either water temperature or the interaction between temperature and elemental concentration, but the direction of the temperature effect differed for each element. Patterns in our partition coefficients are consistent with the idea that uptake of strontium facilitates uptake of barium. Overall, yellow perch otolith element composition was influenced primarily by ambient Sr and Ba concentrations, but temperature could potentially confound the results of otolith microchemistry studies.