We have investigated the effectiveness of using the Micropterus salmoides largemouth bass, which is a top predator found throughout the world, as the index of a hydrosphere environment and its food chain. To this end, we used stable carbon and nitrogen isotope analysis (SIA). Largemouth bass were collected from eight dam reservoirs and two ponds in Toyama Prefecture, Japan. Toyama is located in central Japan and features a variety of distinct geographical environments, a result of the 3000-m elevation that changes over short distances, and abundant water systems. The mean δ13C and δ15N values for the lipid-extracted muscle of largemouth bass from all sampling locations showed large variability, but there were only small standard deviations at each sampling location. The isotope ratios for largemouth bass express the characteristics of each investigated hydrosphere environment and food chain. A very high correlation (δ13C: Yscale = 0.96 Xmuscle + 1.58, R2 = 0.98, δ15N: Yscale = 0.92 Xmuscle – 1.15, R2 = 0.95) of SIA values was found between largemouth bass scales and lipid-extracted muscles, which suggests that the more easily analyzed scales are useful as SIA samples for the monitoring and comparison of hydrosphere environments throughout the world. Copyright © 2011 John Wiley & Sons, Ltd.