In feeding marine wildlife, tourists can impact animals in ways that are not immediately apparent (i.e. morbidity vs. mortality/reproductive failure). Inventorying the health status of wildlife with physiological indicators can provide crucial information on the immediate status of organisms and long-term consequences. However, because tourists are attempting to maximize their own satisfaction, encouraging the willingness to accept management regulations also requires careful consideration of the human dimensions of the system. Without such socio-ecological measures, the wildlife-tourism system may fall into a trap—a lose–lose situation where the pressure imposed by the social system (tourist expectations) has costs for the ecological system (maladaptive behaviours, health), which in turn feed back into the social system (shift in tourist typography, loss of revenue, decreased satisfaction), resulting in the demise of both systems (exhaustion). Effective selection and communication of physiological metrics of wildlife health is key to minimizing problem-causing and problem-enhancing feedbacks in social-ecological systems. This guiding principle is highlighted in the case study presented here on the socio-ecological research and management success of feeding southern stingrays (Hypanus americanus) as a marine tourism attraction at Grand Cayman, Cayman Islands.