LAUSR

Despite the global growth of marine wildlife tourism, potential physiological effects on teleosts remain poorly understood. Physiological responses are important indicators of individual health that may precede population‐level impacts; thus, their evaluation is essential for sustainability. We assessed immunological and general health indices in two marine reef fish species—the rockfish Sebastes oculatus and the Patagonian grouper Acanthistius patachonicus —exposed to long‐term scuba‐diving tourism. We compared fish from moderately—and heavily visited reefs to those from control (unvisited) reefs. The idiosyncratic patterns observed provided no evidence consistent with impaired immune function or general health in response to diver presence. These outcomes could indicate that fishes have become habituated to diver presence, that more sensitive individuals have been selectively displaced to undisturbed areas and/or the intensity and nature of scuba‐diving practices in our study system are below thresholds that would trigger physiological changes. Beyond the ecological significance, our findings provide valuable insights for the sustainable management of marine wildlife tourism. The absence of a clear physiological response in Patagonian grouper and rockfish suggests that properly managed scuba‐diving tourism can be compatible with marine conservation goals. Nonetheless, ongoing monitoring is essential to ensure the long‐term health of fish populations and the sustainability of tourism in these ecosystems.