Dolphins and orcas kept in marine parks have shorter lifespans and higher rates of psychological distress than their wild counterparts. The evidence against marine mammal captivity is strong and has driven significant policy change.
Marine mammal captivity welfare evidence is among the clearest in animal welfare science. The physiological, social, and cognitive needs of dolphins and orcas cannot be met in concrete tanks. Stereotypic behaviours including pacing, floating listlessly, and repetitive circling are common. Aggression between incompatible social groups — forced by captivity — causes injuries. Acoustic environment in concrete tanks is radically different from the open ocean, impairing echolocation and communication. The public entertainment purpose of captivity, which lacks the conservation justification of some zoo programmes, makes the welfare cost harder to justify. Consumer decisions not to visit marine parks, and advocacy for retirement of existing captive cetaceans to sea sanctuaries, are the most direct welfare interventions available.