Individual variation of boldness in free-ranging bottlenose dolphins (Tursiops truncatus) interacting with scuba divers in French Polynesia

Abstract

Marine wildlife tourism is known to affect target species across multiple spatial and temporal scales, from short-term behavioral responses to changes in relative abundance and habitat use patterns. However, despite a growing number of population-, community-, and group-level studies, a limited number of them have focused their research on individual responses to wildlife tourism, particularly on free-ranging cetaceans. Between 2018 and 2020, we investigated the behavioral responses of 20 non-provisioned bottlenose dolphins (Tursiops truncatus) to recreational scuba divers in Rangiroa Atoll, French Polynesia, to understand whether these individuals that had been repeatedly exposed to scuba diving tourism on at least one year exhibited temperament traits along the ‘shyness-boldness’ axis. We also considered potential variation in boldness in relation to sex, age, and tourist-site fidelity. The study documented individual differences in the dolphins’ boldness. There was no variation in boldness according to sex and tourist-site fidelity, but age significantly influenced the dolphins’ boldness with immature dolphins being bolder than mature individuals. The more extreme case of boldness involved four dolphins that tolerated repeated physical interactions with scuba divers. In Rangiroa, scuba diving tourism promotes repeated intrusive interactions with dolphins that might make bold individuals particularly vulnerable to collateral threats associated with human activities. It is therefore crucial to consider individual variation in the dolphins’ behavioral responses to tourism to implement optimal tourism management measures. We suggest in the discussion recommendations to help minimize the risks for both the dolphins and humans associated with repeated close interactions.