‘The Bold are the Sociable’: Personality traits and laterality in an indigenous megafish, the Deccan Mahseer (Tor khudree)

Abstract

The present study explored the relationships between the personality traits boldness, activity, exploration, and sociability, and lateralized utilisation of brain hemispheres in the hatchery-reared juveniles of Deccan Mahseer (Tor khudree), an endangered megafish inhabiting the rivers of central and southern India. Our results revealed a significant positive correlation between boldness, activity and exploratory traits in this species when tested in isolation. Boldness was also positively correlated with the time spent near a conspecific individual, but not with an alien invasive heterospecific tilapia (Oreochromis mossambicus). Although juvenile Deccan Mahseer exhibited significantly greater preference towards conspecific over heterospecific, no divergence in the utilisation of right or left eye was seen while observing these individuals, suggesting the lack of lateralised utilisation of brain hemispheres. Furthermore, laterality in visual perception did not show any significant correlation with any of the personality traits tested in this species. Positive correlations between boldness and sociability in hatchery-reared mahseer populations could result in divergent patterns of dispersion, while absence of laterality may reflect cognitive deficits induced by homogeneous rearing conditions. A greater understanding of such behavioural patterns could help improve rearing practices and inform release protocols for the purposes of conservation of this endangered species.