Comparative Assessment of Fish Species Diversity across Coastal and Inland Regions of Southern Tamil Nadu

Abstract

Fish markets provide valuable, low-cost proxies for assessing regional biodiversity, trade
dynamics, and exploitation patterns. The present study documents and compares fish species
diversity in major markets of three ecologically distinct districts of southern Tamil Nadu—
Kanyakumari (coastal), Tirunelveli (transitional), and Tenkasi (inland). Market surveys
conducted from July to September 2025 recorded 22 fish species belonging to 20 families. Species
were identified using scientific reference and morphological validation, and classified by
taxonomic family, habitat preference, feeding guild, and conservation status. Marine species
dominated overall market composition (77.8%), particularly in Kanyakumari, while Tirunelveli
exhibited a mixed marine–freshwater assemblage and Tenkasi showed limited diversity dependent
on transported marine catches. Carnivorous species constituted the dominant trophic guild (63%),
indicating selective exploitation. Diversity indices revealed highest evenness and richness in
coastal markets. The study highlights the utility of market-based surveys in identifying biodiversity
patterns, trophic biases, and conservation concerns, emphasizing the need for diversified
utilization and sustainable fisheries management in southern India.