Diet analysis allows exploring how coastal dolphins interact with the environment and their role in the marine food webs. We studied the diet and feeding ecology of the Guiana dolphin, Sotalia guianensis, through analysis of stomach content from 42 animals stranded on the eastern coast of Brazil. A total of 1,336 semidigested prey items (fish, otoliths, cephalopod beaks, and crustaceans) were identified. Teleost fish comprised the most frequent food item (92% of the total), followed by cephalopods, and crustaceans. Prey belonged to 34 taxa and richness in individual stomachs varied from 1 to 15 prey taxa. Prey were generally small, but showed a significant trend to increase in size with dolphin length. The main prey of Guiana dolphins were demersal, estuarine, and sound‐making fish such as catfish and sciaenids. No sex‐related differences in diet were found. Diet composition varied seasonally and occurrence of prey items was coherent with breeding or high abundance periods of some fish species and squids. Our study shows the importance of demersal prey from estuarine and soft‐sediment habitats to Guiana dolphin in the Abrolhos Bank and reveals that feeding habits are generalist and opportunistic, with diet reflecting the seasonal abundance and availability of prey.

中文翻译：

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巴西阿伯罗霍斯银行的圭亚那海豚（Sotalia guianensis）的饮食和觅食机会

饮食分析可以探索沿海海豚如何与环境相互作用以及它们在海洋食物网中的作用。我们研究了圭亚那海豚的饮食和喂养生态，Sotalia花草，通过分析滞留在巴西东部沿海地区的42只动物的胃中含量来进行分析。总共发现了1336种半消化的猎物（鱼，耳石，头足类喙和甲壳类动物）。硬骨鱼类是最常见的食物（占总数的92％），其次是头足类和甲壳类。猎物属于34个分类单元，单个胃中的丰富度从1到15个猎物分类单元不等。猎物通常很小，但是随着海豚长度的增加，猎物呈现出明显的增大趋势。圭亚那海豚的主要猎物是海底鱼类，河口鱼类和发声鱼类，例如cat鱼和sciaenids。在饮食方面未发现性别相关差异。饲料组成随季节变化，猎物的发生与某些鱼类和鱿鱼的繁殖或丰度高有关。