The agency is under a court-ordered deadline to decide on a listing petition filed three years ago by the Center for Biological Diversity. The group claims walrus are threatened by a loss of sea ice.
Agency spokesman Bruce Woods says decisions are announced a day before they are published in the Federal Register.
In three of the last four years, walrus have congregated by the thousands on Alaska's northwest shore as sea ice melted beyond shallow continental shelf waters where the animals dive for clams and other prey.
