Faculty of Engineering, Kyushu University, 774, Motooka, Nishi-Ku, Fukuoka, 819-0395, Japan.
Faculty of Bioresource Sciences, Akita Prefectural University, 241-438, Kaido-Bata Nishi, Shimoshinjo-Nakano, Akita, 010-0195, Japan.
Oecologia. 2023 Aug;202(4):743-755. doi: 10.1007/s00442-023-05433-7. Epub 2023 Aug 11.
An adequate supply of food sources with high levels (i.e., weight proportion of total fatty acids) and contents (i.e., absolute amount per mass) of long chain polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are important for ecosystems. Therefore, the supply of EPA and DHA from basal food sources is a useful indicator of ecosystem health. To determine whether EPA and DHA levels and contents in fish can be used as indicators of EPA and DHA supply in lakes, five dominant species of fish and basal food sources (seston and sediment) were collected monthly from June to November from 2016 to 2021 from Lake Hachiro, Japan. Seston and Hypomesus nipponensis were collected from 12 lakes (one collection per lake) with varying seston contents in EPA and DHA. The trends of EPA and DHA in all fish species were similar to those of the basal food sources. Correlation analysis showed that the EPA levels were strongly correlated between fish and seston; moreover, the correlation coefficient increased when a 1- or 2-month moving average was applied to the basal food sources, suggesting that fish represent a time-integrated supply of EPA and DHA. EPA levels of H. nipponensis had the highest correlation coefficients with seston among all fish species. EPA levels of H. nipponensis were significantly correlated with those of seston among lakes. The results of this study suggest that H. nipponensis is a useful indicator of EPA and DHA supplies in lake ecosystems.
食物源中长链多不饱和脂肪酸（如二十碳五烯酸（EPA）和二十二碳六烯酸（DHA））的含量（即总脂肪酸中重量比例）和水平（即单位质量的绝对量）充足对生态系统很重要。因此，从基础食物源中提供 EPA 和 DHA 是衡量生态系统健康的一个有用指标。为了确定鱼类中 EPA 和 DHA 的水平和含量是否可以作为湖泊中 EPA 和 DHA 供应的指标，本研究从 2016 年至 2021 年 6 月至 11 月，每月从日本八代湖采集 5 种主要鱼类和基础食物源（水层悬浮物和底泥）。从 EPA 和 DHA 含量不同的 12 个湖泊（每个湖泊采集 1 个样本）采集水层悬浮物和日本七鳃鳗。所有鱼类物种的 EPA 和 DHA 趋势与基础食物源相似。相关分析表明，鱼类和水层悬浮物之间的 EPA 水平具有很强的相关性；此外，当对基础食物源应用 1 个月或 2 个月的移动平均值时，相关系数增加，表明鱼类代表 EPA 和 DHA 的时间综合供应。在所有鱼类物种中，日本七鳃鳗的 EPA 水平与水层悬浮物的相关系数最高。日本七鳃鳗的 EPA 水平与湖泊之间的水层悬浮物显著相关。本研究结果表明，日本七鳃鳗是湖泊生态系统 EPA 和 DHA 供应的有用指标。
