Food habits of three non-native cichlid fishes in the lowermost Chao Phraya River basin, Thailand

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.

Keywords:

• Chao Phraya River
• cichlid
• food habits
• non-native species
• stomach contents analysis

Acknowledgements

We appreciate the financial support provided by a scholarship for Japanese students through the Heiwa Nakajima Foundation. We thank Dr. Anong Chirapart, Dr. Charumas Meksumpun and Dr. Shettapong Meksumpun for their help and advice in fieldwork and research techniques. Pakorn Tongboonkua, Suchati Taothong and Mr. Saiyon Nakkamin assisted with field sampling and interviews with local people, and their help is greatly appreciated. Finally, we thank the local people and the people concerned who helped to complete the field survey.

Disclosure statement

The authors declare that there is no conflict of interest regarding the publication of this article.

Notes on contributors

Daiki Tomojiri is a postgraduate in invasion ecology and area studies in Graduate School of Asian and African Area Studies, Kyoto University.

Prachya Musikasinthorn is an assistant professor of Department of Fishery Biology, Faculty of Fisheries, Kasetsart University, Thailand, where he conducts research on taxonomy, systematics and biogeography of freshwater fishes of southern Asia. He also conducts surveys on alien fish species in the region.

Akihisa Iwata is a professor of Kyoto University, Japan, where he conducts research on fish taxonomy, ecology and conservation biology including alien species problems in East and Southeast Asia.