Evaluating and minimising social stress in the care of captive bottlenose dolphins (Tursiops aduncus)

Stress can increase an organism's susceptibility to disease. Thus, managing stress and its causes are important elements of captive care. Social factors such as changes in group dynamics, competition over resources, and unstable dominance hierarchies are potential stressors for highly social animals such as bottlenose dolphins (Tursiops sp). We present three case studies of mortality and illness in captive bottlenose dolphins and suggest that stress, resulting from social instability and ensuing aggressive interactions, is likely to have played a role in these health consequences. Stress is implicated by blood profiles, loss of appetite, and gastric ulcers, and social problems and instability are evident in the quantitative analysis of individual activity levels and association patterns. This is a unique study on marine mammals in that it demonstrates a correlation between quantitative behavioral indices and physiological measures of stress and health. Recommendations are made for the management of captive dolphins including regular quantitative assessment of behavior and associations and maintenance of appropriate groupings of age and sex classes. Behavioral records can be an important early indicator of health problems and may also serve as a useful tool for recognizing potentially stressful social changes and circumstances. Zoo Biol 21:5-26,2002. (C) 2002 Wiley-Liss, Inc.