Information on the feeding habits of species is essential to develop appropriate conservation actions. This study aimed to assess spatial and temporal variation in the diet of the Eurasian otter, Lutra lutra in the Anzali Wetland, through fecal and stable isotope analysis. Seven main prey items were observed in the analysis of 300 fresh spraints. The highest feeding index was observed for fish, followed by snakes. Among the fish species consumed, the index of preponderance of Prussian carp (Carassius gibelio) was the highest followed by pike (Esox lucius) and white bream (Blicca bjoerkna). Results of Shannon diversity index suggest spatial variation of species diversity within and between feeding items (p < 0.05); snakes, frogs, and oriental river prawn (Macrobrachium nipponense) showed a seasonal variation. The otter’s trophic level (TL) (3.79) was higher than the TLs of other Anzali Wetland predators, such as pike. Bayesian mixing model showed source proportion contributions of fish 49.5%, reptiles 16.7%, insects 14.8%, crustacean 10.5%, amphibians 4.3%, birds 4.1%, and mollusks 0.1%. When considering only fish species in the Bayesian mixing model, Prussian carp was the main fish prey in the otters’ diet accounting for 47%. Based on the results of this study, the Eurasian otter plays an important role in the ecology of the Anzali Wetland ecosystem even though it preys on exotic species, such as the Prussian carp and the oriental river prawn.

有关物种摄食习惯的信息对于制定适当的保护措施至关重要。这项研究的目的是评估在欧亚水獭，饮食时空变化水獭在安扎湿地，通过粪便和稳定同位素分析。在分析300个新鲜扭伤时观察到七个主要猎物。鱼的摄食指数最高，其次是蛇。在食用的鱼类中，普鲁士鲤鱼（Carassius gibelio）的优势指数最高，其次是梭子鱼（Esox lucius）和白鲷（Blicca bjoerkna）。香农多样性指数的结果表明，饲喂物品内和饲料之间物种多样性的空间变异（p <0.05）; 蛇，青蛙和东方河虾（Macrobrachium nipponense）表现出季节性变化。水獭的营养水平（TL）（3.79）高于其他安扎利湿地捕食者（例如长矛）的TL。贝叶斯混合模型显示鱼的来源比例贡献为49.5％，爬行动物为16.7％，昆虫为14.8％，甲壳类为10.5％，两栖动物为4.3％，禽类为4.1％，软体动物为0.1％。在贝叶斯混合模型中仅考虑鱼类时，普鲁士鲤鱼是水獭日粮中的主要猎物，占47％。根据这项研究的结果，尽管欧亚水獭捕食普鲁士鲤鱼和东方河虾等外来物种，但它在安扎利湿地生态系统的生态中起着重要作用。