Kin vs Invader? Influence of Invasive Alien Fish on Social Decision-Making in Juvenile Deccan Mahseer, a Megafish
Speaker : Ayana Krishnan
Ph.D. Scholar, School of Natural Sciences and Engineering, NIAS
@ : ayana@nias.res.in
Chairperson : Hashim Mohammed S
Ph.D. Scholar, School of Natural Sciences and Engineering, NIAS
@ :mohammedhash@nias.res.in
Date : 29th July 2026
Time : 9.30 AM
Venue : Lecture Hall
Abstract: Fish groups are fission-fusion societies where an individual’s decision to leave or join a shoal (group of fishes comprising of same or different species) has biological fitness consequences. Understanding the determinants of social decision-making in fishes, particularly in species that are restocked into the natural environments is crucial in the current context of rapid extension of the distribution range and increasing population size of the Invasive Alien Fishes (IAF) in the natural water bodies. This presentation will elaborate the social decision-making by hatchery reared Juveniles of Deccan Mahseer (Tor khudree), a charismatic freshwater megafish species, when tested with monospecific shoals of JDM and Mozambique tilapia (Oreochromis mossambicus) and common carp (Cyprinus carpio) commonly found IAF in Indian waterbodies, as stimuli. The ecological and conservation salience of the modulations observed in the social decision-making strategies in response to the variation in shoal size of conspecifics and IAF, and mixed species shoals by the juveniles of T. khudree, a fish of high environmental, economic and cultural importance and a species extensively restocked in different riverine ecosystems of India, will also be discussed.
About the speaker: Ayana Krishnan is a 2nd year Ph.D. Student at the School of Natural Sciences and Engineering, National Institute of Advanced Studies, Bangalore. Her research interests are behavioural ecology, stakeholder-involved species distribution mapping, habitat suitability assessment and restocking and reintroduction of the freshwater megafishes. She aims to develop intervention programmes and policy recommendation to strengthen the evidence-based conservation and management of the iconic megafishes, mahseer in the Cauvery River Basin.