Preliminary Checklist of Freshwater Fishes from the Eraviperoor Region of the Manimala River, Kerala, India

Abstract

The Western Ghats of India, a UNESCO World Heritage Site and globally recognized biodiversity hotspot, support exceptionally high freshwater fish diversity and endemism, particularly in the southern region, making them a critical area for ichthyological research and conservation. The present study provides a preliminary checklist of freshwater fishes recorded from the Eraviperoor region of the Manimala River, Kerala. The Manimala River is a west-flowing river draining the southern Western Ghats biodiversity hotspot. Fish samples were collected from January to April 2026 using gill nets, cast nets, and traditional trap nets. A total of 17 fish species belonging to 17 genera, 13 families, and 9 orders were recorded during the survey. The order Cypriniformes was the most species-rich, represented by four species, followed by Siluriformes and Anabantiformes with four and three species, respectively. Among the recorded species, eight (47.06%) were categorized as Least Concern (LC), two (11.76%) as Vulnerable (VU), one (5.88%) as Near Threatened (NT), and one (5.88%) as Data Deficient (DD) according to the IUCN Red List. Three species had not yet been assessed by the IUCN. Two species, Pangasianodon hypophthalmus and Labeo rohita, were identified as exotic to the river system. Notably, the checklist includes recently described taxa such as Heteropneustes fuscus Plamoottil, 2021 (Travancore Black Stinging Catfish), and Pristolepis rubripinnis Britz, Kumar & Baby, 2012 (Red-finned Catopra). As the survey was conducted at a single sampling station, the checklist does not represent the complete ichthyofaunal diversity of the Manimala River. The occurrence of threatened and endemic species, together with exotic fishes, highlights the conservation importance of the Manimala River and underscores the need for further comprehensive biodiversity assessments.