The Pacific walrus will not be designated as endangered or threatened under the Endangered Species Act, the Fish and Wildlife Service announced Wednesday, reversing an Obama administration finding that the walrus deserved protections because of the effects of global warming and receding Arctic sea ice.

“Their thorough review, driven by the best available data and science, found that the population of Pacific walrus is robust and healthy, and has proven that it can adapt to the changing conditions in the Arctic,” said Sen. Lisa Murkowski, R-Alaska, who is chairwoman of the Senate Energy and Natural Resources Committee.