The Marine Mammal Protection Act of 1972

The Marine Mammal Protection Act is a sweeping piece of legislation passed in 1972 by President Richard Nixon. The law prohibits the 'taking' (capturing or removing), and the import or export of live marine mammals or marine mammal products except by permit. Although the Nixon Administration wasn't known for the value they placed on the environment, this piece of legislation is a monument. Almost no other country protects marine mammals the way we do in the United States. 

You may have noticed the 'except by permit' part of my synthesis of the MMPA. Permits were most commonly issued in the years directly following the passing of this law, as orca captors in the Pacific Northwest sought to continue their businesses. However, the limits on the number of permits and the stringent requirements for animal care and capture methods effectively killed the industry in the US. Today, the law is enforced with much rigidity. Although import and export permits are still applied for, their issuance is much more strained. An example of these permits going through successfully for the applicants would be killer whale artificial insemination. SeaWorld had to apply to import Kshamenk's sperm, and to export that of Ulises before ending the practice of breeding altogether.