Sea otter

The number of southern sea otters living off the Californian coast shot up after the animals gained protection from the US Endangered Species Act. Credit: Inaki Relanzon/NPL

Conservation biology

Rare whales and seals thrive thanks to controversial US law

Animals protected by the Endangered Species Act for more than two decades are the most likely to recover.

Populations of whales, seals, sea otters, manatees and sea turtles are bouncing back under the protection of the US Endangered Species Act, even after decades of habitat destruction and exploitation.

The act is designed to protect imperilled wildlife, but the Trump administration views the law as an unnecessary burden and has introduced at least 75 bills seeking to weaken it.

To test the act’s effectiveness, Abel Valdivia at the Center for Biological Diversity in Oakland, California, and his colleagues examined populations of 14 marine mammal species and 5 sea turtle species protected by the act. Out of a total of 31 populations, the team found that 24 had recovered significantly since the animals were listed as endangered or threatened. Recovery was most likely for species that had received protection for more than 20 years.

The trend implies that vulnerable marine species in the United States survive largely because of the act’s protection, the authors say.