Meta-analyses of whale-watching impact studies: comparisons of cetacean responses to disturbance

Whale-watching activities can induce behavioral changes that may negatively affect cetacean populations. However, these changes may vary depending on species, populations and environmental features. It is important to determine inter-specific variation in cetacean responses to stressors in order to identify the best metrics for evaluation of consequences of anthropogenic disturbance. We used meta-analyses to assess the consistency of cetacean responses to whale-watching vessels across a pool of suitable studies covering a variety of species and sites. We analyzed several metrics to capture cetacean heterogeneous responses and to explore their reliability across species. We found disruptions of activity budget and of path directionality as the most consistent responses towards whale-watching vessels. In a similar manner across species, animals were more likely to travel and less likely to rest and forage in the presence of vessels. Cetaceans also showed a tendency to increase path sinuosity (deviation index) and decrease path linearity (directness index) during boat interactions. We also explored the influence of socio-ecological factors on behavioral response but found no consistent results among studies. Further population-specific studies should address the potential long-term consequences of these behavioral responses to inform management of the whale-watching industry.