Fish Migration Patterns and Taxonomic Diversity in the Mahanadi Estuarine System, India: A Comprehensive Synthesis
Subash Chandra Bemal
Department of Zoology, Maa Manikeshwari University, Bhawanipatna, Kalahandi, Odisha, Pin 766001, India.
Roshan Dhangadamajhi
Department of Zoology, Maa Manikeshwari University, Bhawanipatna, Kalahandi, Odisha, Pin 766001, India.
Swagatika Mishra
Department of Zoology, Maa Manikeshwari University, Bhawanipatna, Kalahandi, Odisha, Pin 766001, India.
Nikita Naik
Department of Zoology, Maa Manikeshwari University, Bhawanipatna, Kalahandi, Odisha, Pin 766001, India.
Subhra Mishra
Department of Zoology, Maa Manikeshwari University, Bhawanipatna, Kalahandi, Odisha, Pin 766001, India.
Subrat Kumar Panigrahi
*
Department of Zoology, Maa Manikeshwari University, Bhawanipatna, Kalahandi, Odisha, Pin 766001, India.
*Author to whom correspondence should be addressed.
Abstract
Background: The Mahanadi Estuarine System is located on the east coast of Odisha, India. Despite numerous studies on its ichthyofauna, a comprehensive synthesis of fish diversity and migration guild structure has been lacking.
Methods: A narrative review and limited meta-analysis of published literature were conducted to compile fish diversity records from the Mahanadi Estuarine System. Fish species were classified into six migration guilds: amphidromous, anadromous, catadromous, oceanodromous, potamodromous, and non-migratory. Taxonomic composition and diversity indices were calculated using the compiled dataset.
Results: For the Mahanadi Estuarine System, a total of 153 fish species representing 116 genera, 59 families, and 23 orders were recorded. Migration guild analysis identified six migratory categories, comprising 46 amphidromous species (30.07%), 23 potamodromous species (15.03%), 17 oceanodromous species (11.11%), 11 anadromous species (7.19%), 8 catadromous species (5.23%), and 1 non-migratory species (0.65%). Diversity analysis yielded a Shannon–Wiener diversity index (H′) of 2.69, Simpson’s diversity index (1−D) of 0.912, Pielou’s evenness index (J′) of 0.859, Margalef’s richness index of 4.37, Menhinick’s richness index of 1.86, and a Berger–Parker dominance index of 0.163. Among the recorded orders, Clupeiformes comprised 25 species (16.34% of the total species richness), followed by Siluriformes with 22 species and Eupercaria with 17 species. Taxonomic composition analysis revealed 1.32 species per genus, 2.59 species per family, and 6.65 species per order. In addition, the average numbers of genera per family and families per order were 1.97 and 2.57, respectively.
Conclusion: The Mahanadi Estuarine System harbours a highly diverse fish assemblage comprising 153 species belonging to 116 genera, 59 families, and 23 orders, with migratory fishes representing a major component of the community. The occurrence of multiple migratory guilds together with high diversity, richness, and evenness values highlights the ecological significance of the estuary and provides a valuable baseline for future biodiversity conservation, fisheries management, and ecological monitoring.
Keywords: Mahanadi Estuarine System (MES), estuarine fishes, ichthyofaunal diversity, fish migration, migration guilds, taxonomic richness, habitat association, Clupeiformes, river–estuary connectivity, biodiversity baseline