Abstract The food habits of three non-native cichlid fishes, Mayan cichlid (Mayaheros urophthalmus), Mozambique tilapia (Oreochromis mossambicus) and Nile tilapia (O. niloticus), in the lowermost Chao Phraya River basin, Thailand, was examined by stomach contents analysis. The index of preponderance, an index of the importance of prey items, was calculated from two relative metrics of prey quantity: percent frequency and percent volume. The index of niche breadth and the overlap coefficient were calculated to compare the breadth of food habits among the size classes and species groups. The M. urophthalmus mainly preyed on fish scales, detritus and aquatic invertebrates (molluscs and crustaceans). The O. mossambicus and O. niloticus fed mostly on detritus. The diets of the latter two species overlapped almost completely; however, green filamentous algae mixed with detritus was observed in the diet of the O. niloticus only. The observation that fish scales were a predominant food source in the stomach of M. urophthalmus (high importance value 45.48%) was specific to this study area.

中文翻译：

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泰国湄南河流域最下游三种非本地慈鲷鱼的饮食习性

摘要 通过胃内容物分析研究了泰国湄南河流域最下游的玛雅慈鲷 (Mayaheros urophthalmus)、莫桑比克罗非鱼 (Oreochromis mossambicus) 和尼罗罗非鱼 (O. niloticus) 三种非本地慈鲷的饮食习性。 . 优势指数是衡量猎物重要性的指标，它是根据猎物数量的两个相对指标计算得出的：频率百分比和体积百分比。计算生态位宽度指数和重叠系数，以比较大小等级和物种组之间的食物习性宽度。M. urophthalmus 主要捕食鱼鳞、碎屑和水生无脊椎动物（软体动物和甲壳类动物）。O. mossambicus 和 O. niloticus 主要以碎屑为食。后两个物种的饮食几乎完全重叠；然而，仅在 O. niloticus 的饮食中观察到混合有碎屑的绿色丝状藻类。观察到鱼鳞是 M. urophthalmus 胃中的主要食物来源（高重要性值 45.48%）是该研究区域特有的。