Over the years, marine mammal populations have been severely depleted due to human activities. Because of this, a number of international treaties and national laws have been set up to protect these creatures.  One of the first such treaty was set up by the International Whaling Commission.  In 1946 this group originally formed to help regulate whaling in response to depleted stock.  However, as whale products grew less popular, this group shifted focus, and in 1982 it set up the first international ban on all commercial whaling.  One major problem that this Commission still faces is that membership is voluntary, and some countries such as Japan and Norway insist on determining their own strategies concerning whaling.

The first laws in the United States protecting marine mammals contained many loopholes that made them inadequate. For example, the North Pacific Fur Seal Act of 1966 only protected the Northern Fur Seal and the Sea Otter from high seas hunting, when their most serious threats were found in in-shore waters.  The Endangered Species Conservation Act of 1969 also failed to protect those marine mammals most at risk.  State laws were also inconsistent or even non-existent in many coastal states.  It was with these concerns in mind when the US congress drafted the Marine Mammal Protection Act in 1972.

The Marine Mammal Protection Act provides the present legal framework for US conservation of marine mammals and their habitats.  It was the first law to uniformly cover all marine mammals.  Since its enactment, most parties seeking to use these animals for economic gain have not been granted the right by the courts.  It states that all marine mammal populations should be brought to and maintained at  their optimum sustainable population.  Although only a law within the US, this Act also influences international trade by restricting imports of marine mammals and their products.  The few exceptions for the taking of marine mammals under this law include scientific research, public display, photography for educational or commercial purposes, enhancing the survival or recovery of a species or stock, the incidental taking during a commercial fisheries operation, the incidental taking by private citizens, taking by native tribes, and the taking by non lethal means to protect personal safety or private property in self defense.  Since it was enacted, many amendments have been made to the Marine Mammal act to ensure that these animals are being protected, such as the amendments of the 1970s in response to the fishing industry catching marine mammals in their nets. The results of this was that the number of dolphins who died in fishery nets decreased substantially from 368,600 (1972) to 15,305 (1980).

A year after the Marine Mammal Act was passed, the US Congress enacted another law that gave several specific marine mammals additional protection.  The Endangered Species Act of 1973 established conservation regulations for specific plant and animal species considered in danger of extinction.  The law was subsequently modified to include habitat modification as a serious threat that could harm listed species.  Marine mammals protected by the endangered species act include nine species of whales; the Stellar sea lion, the Hawaiian, Mediterranean, and Caribbean monk seals; the Guadeloupe fur seal; the Ringed Seal of lake Saimaa; the marine otter of South America; the southern population of Sea Otter; all Sirenians; two species of river dolphins; and the Vaquita.  One animal that has greatly benefited from the protection of the endangered species act is the West Indian Manatee of Florida.  This act helped push through various boating laws that have allowed these animals more protection from the threat of boat collisions and habitat loss due to the building of docks.

The National Environmental Policy Act sets up procedural requirements concerning the environmental impact of industry.  It has for years provided much information about how marine mammals are effected by human activity as well as forced people to seek alternative strategies to minimize the risks of industry to the environment.  

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) has secured cooperation of many countries in regulating trade that might threaten certain species.  It offers certain protections to endangered and threatened species.  All cetaceans, sirenians, marine otters, and 14 species of pinniped are currently listed on CITES appendices.

The Animal Welfare Act focuses on animals in captivity, such as a lab or an aquarium, and how they should be cared for and maintained.  Concerning marine mammals, it ensures they are provided humane care and treatment during transportation as well as at their permanent location once they arrive.  There is concern by many that this act does not set up sufficient standards to protect captive marine mammals, and there is much criticism regarding the holding of them in captivity. 

In 1973, the five nations within the polar bear's territory agreed that the bears were at considerable risk due to over-hunting and threats to their habitat.  This led to the adoption of the Agreement for the Conservation of Polar Bears, which prohibited the taking (hunting, killing, capturing) of them except for research or traditional tribal reasons.  It put special focus on setting up sound conservation practices with attention on their denning, feeding, and migratory grounds.

All of these laws and treaties together have allowed many marine mammal species to rebuild their populations and reclaim some of their previous ranges.  They have provided much security to marine mammal populations, but more is needed, especially in regards to industrial management, to ensure the survival of these species.