In the United States, the Marine Mammal Protection Act of 1972 protects marine mammals both in human care and in the wild.
For a facility to display marine mammals federal permits are required and standards for their care and maintenance must be met. Some of these standards include pool size, water quality, and fish storage and preparation.
In the wild, it is prohibited to hunt, harass, approach, swim with, or feed marine mammals.
The dolphin seen on restaurant menus in the United States is a fish (mahi mahi or dorado) and is unrelated to the dolphin mammal.