New Distributional Records of 31 Marine Fish Species from Rocky Reefs of Kerala: Insights from Underwater Visual Census on the Southwest Coast of India

Ichthyofaunal diversity monitoring through in-situ approaches is crucial in critical habitats like rocky reefs, which serves critical ecological role including feeding, breeding, and nursery grounds for various marine organisms.However, these ecosystems face significant threats like habitat loss, pollution, climate change, and overfishing.This study evaluates the efficacy of underwater visual census (UVS) in documenting rocky reef associated fish diversity along the Kerala coast, southwest coast of India.Underwater surveys were conducted between December 2013 and February 2018 across varying reef habitats, including shallow waters of reefs (1m), intertidal reef (1-5 m), and adjacent sandy bottom of reefs (06 -12 m).The study documented ichthyofaunal diversity and used extrapolation and modelling to predict species diversity at depths of 15-30 m.A total of 232 fish species were recorded, representing two classes, 16 orders, 62 families, and 114 genera.Notably, 31 species from 17 families and 24 genera had extended distribution ranges within the IndianOcean and India.Among this, 13 species were identified as first report from Indian waters, and 18 were new regional distributional records from Kerala coast.This study underscores the significance of in-situ approaches such as UVS in biodiversity assessments of rocky reef ecosystems.The results were explicating the detailed and follow-up study of reef-associated biodiversity, particularly in species-rich and ecologically sensitive habitats, to enhance conservation and management strategies for marine ecosystems.