The growing popularity of ecotourism is increasing human–wildlife interactions in coral reef ecosystems. Although often considered benign, interactions with humans can alter essential antipredator responses. Reef fish exposed to humans often modify their antipredator behavior. Prior work has shown that fish respond differently in marine protected vs. non-protected areas (MPAs), but it remains unclear whether these differences stem from protection status or differences in human presence. We studied dusky damselfish (Stegastes nigrican) antipredator behavior across three sites separated by MPA status and human activity. We also investigated how different durations of short-term exposure to snorkeler presence influenced risk assessment across these sites. We quantified antipredator responses using: (1) the proportion of time fish were displaced from their territory during different durations of snorkeler exposure, (2) post-treatment flight initiation distance (FID), and (3) latency to return after fleeing. Human presence explained more variation than MPA status in all metrics. Fish from reefs with high human presence remained in their territories longer during treatments, had shorter FIDs, and returned faster after fleeing. Our findings suggest that snorkeling induces immediate behavioral changes and alters risk assessment following exposure in damselfish, potentially compromising fitness-promoting behaviors and predation avoidance.
ASHABRANNER et al. (Tue,) studied this question.