Relationships between Water, Otolith, and Scale Chemistries of Westslope Cutthroat Trout from the Coeur d'Alene River, Idaho: The Potential Application of Hard-Part Chemistry to Describe Movements in Freshwater

Abstract
We quantified Mg:Ca, Mn:Ca, Sr:Ca, and Ba:Ca molar ratios from an area representing the summer 2000 growth season on otoliths and scales from 1-year-old westslope cutthroat trout Oncorhyncus clarki lewisi collected from three streams in the Coeur d'Alene River, Idaho, system. We also quantified Mg:Ca, Sr:Ca, and Ba:Ca molar ratios in the water during summer 2000 and used regressions to model the assimilation of the various ratios into the otoliths and scales. Otolith and scale chemistries were linearly related to the Sr:Ca and Ba:Ca ratios in the water. The partition coefficients for the Sr:Ca ratios in otoliths and scales are higher in this freshwater system than in experimental results from a saline environment; we attribute these differences to differences in the biology of saltwater and freshwater fish. In contrast, the Ba:Ca partition coefficients are similar between the two environments, suggesting that our estimates are representative of those for a wide range of concentrations, temperatur...