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Endangered Marine Animals and The Endangered Species Act

The Marine Mammal Center has worked extensively with species that are considered to be endangered or threatened. An endangered species is one that is likely to become extinct and is listed under the U.S. Endangered Species Act or on the International Union for the Conservation of Nature (IUCN) Red List.

In response to recent news about revisions to the Endangered Species Act, The Marine Mammal Center has issued the following statement:
Our ocean is in trouble and marine mammals are facing new threats ranging from warming ocean temperatures to ocean trash and plastic pollution to depletion of fish stocks – just to name a few. Now is not the time to remove protections for threatened and endangered species. The Marine Mammal Center strongly opposes the revisions that weaken implementation of the Endangered Species Act. We will continue our work to ensure protections for threatened and endangered species such as the southern sea otter, Hawaiian monk seal and Guadalupe fur seal.

The U.S. Endangered Species Act (ESA) was passed in 1973 in order to protect plant and animal life that was threatened with extinction as a "consequence of economic growth and development untempered by adequate concern and conservation." The Act was written to protect not only endangered species, but also "the ecosystems upon which they depend." It replaced the Endangered Species Conservation Act of 1969 and was amended in 1978 and 1982. The Endangered Species Act is administered by the United States Fish and Wildlife Service and the National Marine Fisheries Service, a federal agency that is a division of the Department of Commerce.

In addition to the U.S. Endangered Species Act, the International Union for the Conservation of Nature (IUCN) maintains a Red List of Threatened Species for classifying the conservation status of plant and animal species on a global scale.

Read the complete text of the Endangered Species Act.

Read about the Conservation Status of endangered species.

Find out more about the Center's work with endangered marine animals and some of the patients we have treated by viewing the links below.

Hawaiian Monk Seal

The Hawaiian monk seal is listed as Endangered under the ESA. It is the most endangered pinniped species in the United States. The population is currently only about 1,100 and decreasing approximately 4% per year.

Guadalupe Fur Seal

The Guadalupe fur seal is listed as Threatened under the ESA. Their current population is estimated at about 10,000 animals and is slowly recovering from the near extinction it faced in the late 19th century.

Steller Sea Lion

The western population of the Steller sea lion is listed as Endangered under the ESA, while the eastern population was delisted from the List of Endangered and Threatened Wildlife in December, 2013.

Southern Sea Otter

The southern sea otter is listed as Threatened under the ESA. In 2016, the three-year average of the population reached 3,272 animals—a critical step toward the long-term goal of removing them from their ESA listing


The vaquita (Phocoena sinus) is the world's most endangered marine mammal, with latest estimates putting their number at less than 100 animals left in the world. Their remaining habitat is a small area in the northern Gulf of California, Mexico, where they are being caught in fishing gillnets at an alarming rate. This is outside of the rescue range of The Marine Mammal Center, but nevertheless, we want to draw attention to the plight of this cetacean, which could face extinction soon. Find out more about efforts to save the vaquita.


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