Exploring the Freshwater Fish Diversity of the Mahanadi River Basin, India: A Taxonomically Updated and Validated Checklist

Abstract

Background: The Mahanadi River is one of the major river systems of India, supporting a rich diversity of freshwater and estuarine fish communities. However, existing information on its ichthyofaunal diversity is scattered across various publications and often shows taxonomic discrepancies. Therefore, a comprehensive and consolidated synthesis is necessary to provide an updated and reliable account of the fish diversity of the river. Objective: To compile and critically analyse published ichthyofaunal records (1940–2025) to assess taxonomic composition, dominance patterns, and emerging ecological concerns in the Mahanadi basin. Results: A total of 173 fish species belonging to multiple orders and families were documented from the Mahanadi River. Among them, 121 species were food fishes, 20 ornamental fishes, and 32 had both food and ornamental value. According to IUCN status, 137 species were Least Concern, 7 Near Threatened, 5 Vulnerable, 3 Endangered, and 11 Data Deficient and 7 Not Evaluated. The order Cypriniformes, particularly the family Cyprinidae, dominated the assemblage, followed by Siluriformes, indicating high habitat and trophic diversity. Migratory and estuarine-linked species suggest river coastal connectivity. The presence of exotic species such as Oreochromis mossambicus and Cyprinus carpio reflects anthropogenic influence. Conclusion: The basin supports high ichthyofaunal richness shaped by ecological gradients and human interventions, warranting integrated conservation and basin-scale management.