The welfare of dolphins and orcas in marine parks has been the subject of intense scientific and public scrutiny. Research evidence is reshaping standards and public policy.
The welfare case against keeping large cetaceans in captivity rests on evidence that their behavioral, social, and physiological needs cannot be met in marine park environments. Orcas in particular — with vast ranging behavior, complex matrilineal bonds, and sophisticated cultural transmission — show multiple indicators of compromised welfare in captivity: stereotypic swimming, abnormal aggression (toward trainers and other animals), dental wear from biting tank walls, and reduced lifespans. Dolphin welfare in captivity is more nuanced: smaller pools and shows cause measurable stress, but better-designed facilities with larger lagoons and behavioral choices show improved welfare indicators. The ethical trajectory in marine mammal welfare is toward phase-outs of cetacean captivity — particularly for large species — with transition to sea pen sanctuaries as an alternative.