A recent U.S. Geological Survey estimates that the Pacific walrus population nearly halved between 1981 and 1999, the last year for which demographic data are available. The study notes that the decline was most severe in the mid-1980s, and then moderated in the 1990s. Currently, the USGS is working to obtain more recent population data of the Pacific walrus. This information will be vital because the U.S. Fish & Wildlife Service is expected to determine whether the Pacific walrus should be listed as threatened under the Endangered Species Act in 2017.