The U.S. Fish and Wildlife Service ruled last week that Minnesota and Midwestern moose will not be listed as a federally endangered species.

A moose subspecies native to four upper Midwestern states will continue to be left off the federal Endangered Species List.

The U.S. Fish and Wildlife Service on Tuesday ruled that “the northwestern subspecies” is stable, The Associated Press reports. The moose are historically found in Michigan, Minnesota, North Dakota and Wisconsin. The agency also said the subspecies has no notable biological differences from moose across the U.S.-Canada border, where the population is healthy.

“We have to find those moose are distinct from other moose in the same region, and we could not find that,” said agency spokeswoman Georgia Parham.

Environmental groups that filed the 2016 petition seeking federal Endangered Species Act protections for moose are “shocked” by the agency’s decision and may file an appeal or new petition, said Collette Adkins, a biologist and attorney with the Center for Biological Diversity, which filed the petition with Honor the Earth.

The groups filed for federal protections after moose in Minnesota suffered a decade-long steep decline, the report said. The state has the largest population of the subspecies with about 3,150 animals, which has been relatively stable for nine years, according to an aerial study conducted last winter. However, that’s still down more than 50 percent since 2006.

Scientists said the decline in the Minnesota population could be attributed to parasites, disease and wolf predation. The environmental groups also blame a warming climate, The AP reports.

Minnesota and Michigan both list the moose subspecies as an animal of “special concern.” However, Michigan’s population is much smaller: about 600.

Inclusion on the federal list would make it illegal to hunt the species and could mean habitat protections and federally funded research, The AP reports. Michigan, Wisconsin and Minnesota do not allow hunting the moose; North Dakota does.Michigan has two moose herds in the Upper Peninsula. The population in the western Upper Peninsula was airlifted from Canada in the 1980s and is growing steadily at a rate of about 2 percent annually, according the Michigan Department of Natural Resources. The most recent biennial survey conducted in early 2019 counted 509 moose. The native eastern Upper Peninsula population is estimated to be fewer than 100.