‘The Bold are the Sociable’: Personality, sociability and lateralized utilization of brain hemisphere in the juveniles of a megafish Deccan Mahseer ( Tor khudree )

Abstract The present study explored relationships between personality traits; boldness, activity and sociability, and lateralized utilization of brain hemispheres in the hatchery reared juveniles of Deccan Mahseer (Tor khudree), a game fish inhabiting the rivers of central and southern India. Our results revealed a significant positive correlation between boldness and activity in this species when tested in isolation. However, boldness was positively correlated with the time spent near the individual conspecific but not with the individual alien invasive heterospecific tilapia (Oreochromis mossambicus). Although juvenile Deccan mahseer exhibited significant variation in the preference towards conspecific over heterospecific, no divergence in the utilization of right or left eye was seen while observing these individuals suggesting the lack of lateralized utilization of the brain hemispheres. Furthermore, laterality in visual preference failed to show any significant correlation with any of the personality traits tested in this species. Results are discussed in the light of the existing literature on the impact of life in homogenous hatchery conditions on the behaviour, personality traits and cognitive abilities of fishes. Significance statementThe present study is one of the first that focuses on personality and lateralization in Deccan Mahseers, an endangered freshwater megafish. We report a positive linkage between boldness and sociability but do not find any correlation of personality with lateralized utilization of brain hemispheres in diverse social contexts. These findings have implications in the conservation and cultivation of this ecologically, culturally and economically important indigenous fish.