δ13C and δ15N in Micropterus Salmoides largemouth bass and their scales: a freshwater environmental proxy

富山位于日本中部，具有多种独特的地理环境，这是由于3000米的海拔在短距离内变化，以及丰富的水系统。本文测定了8个堰湖和2个水塘中大口黑鲈脂肪提取肌肉的δ13C和δ15N。各采样点大口黑鲈脂质提取肌的δ13C和δ15N均值变异性较大，但各采样点的标准差较小。根据其同位素组成与平均海拔高度和坝水冲刷速率的关系，可将坝湖分为两类。这表明，大口黑鲈的同位素比值反映了所调查水圈环境和食物链的特征。此外，在大口黑鲈鳞片与脂肪提取肌肉之间发现了非常高的同位素值相关性（δ13C, R2= 0.98; δ15N, R2= 0.95），这表明更容易分析的鳞片可以代替肌肉样本用于全球水圈环境的监测和比较。

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. We determined δ13C and δ15N of the lipid-extracted muscles of largemouth bass, a top aquatic predator, from eight dam lakes and two ponds.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 dam lakes could be divided into two groups by their isotopic compositions, as a function of mean altitude and flushing rate of the dam water. Thissuggests that the isotope ratios for largemouth bass express the characteristics of each investigated hydrosphere environment and food chain. Moreover a very high correlation of isotopic values （δ13C, R2= 0.98; δ15N, R2= 0.95) was found between largemouth bass scales and lipid-extracted muscles, suggesting the more easily analyzed scales can replace muscle samples for the monitoring and comparison of hydrosphere environments throughout the world.