Evaluating Tour Boat Compliance With Dolphin-Watching Guidelines in the Sian Ka'an Biosphere Reserve

Boat-based dolphin-watching tourism targeting common bottlenose dolphins (Tursiops truncatus) in the Mexican Caribbean is an increasing activity. Yet, tour boat compliance with local dolphin-watching guidelines has not been evaluated, and the impacts of these activities on local dolphin populations remain unknown. To address this gap, we used boat-based observations and aerial drone video recordings to evaluate tour boat compliance and described bottlenose dolphins' behavioral responses. We assessed tour boat adherence to key local guidelines, including observation time limits, maintaining minimum distances from dolphins, limiting the number of vessels, and controlling vessel speeds during approach and departure. To describe the behavioral responses of dolphins during tour boat activity, we quantified changes in directional movement, group cohesion, and swimming speed during boat interactions. Our findings revealed that 98% of the observed dolphin-watching events (n = 323) were non-compliant, with the most frequent violation being the proximity to dolphins. During boat interactions, 95% of dolphin directional changes were movements away from boat trajectories and 55% showed increased swimming speeds. These results underscore the need for monitoring and enforcing compliance with guidelines in dolphin-watching tourism, aiming to develop strategies to ensure the sustainability of this local tourism practice.