The U.S. Marine Mammal Protection Act protects all marine mammals, including cetaceans (whales, dolphins, and porpoises), pinnipeds (seals and sea lions), sirenians (manatees and dugongs), sea otters, and polar bears within the waters of the United States. The Act makes it illegal to "take" marine mammals without a permit. This means people may not harass, feed, hunt, capture, collect, or kill any marine mammal. The Act also creates the marine mammal stranding network. The National Marine Fisheries web site gives the complete text of the Act.

The MMPA is managed by the federal government. The National Marine Fisheries Service, part of the National Oceanic and Atmospheric Administration within the Department of Commerce, is responsible for managing cetaceans otariids, and phocids. The U.S. Fish and Wildlife Service, part of the Department of the Interior, is responsible for managing odobenids, sirenians, otters, and polar bears. The Animal and Plant Health Inspection Service, part of the Department of Agriculture, is responsible for regulations managing marine mammals in captivity.

Other Protections

Many state and local jurisdictions also have laws to protect marine mammals and endangered species. In addition, international agreements have been negotiated to protect marine mammals.