All plants and animals, except for pest insects, are eligible for listing as endangered or threatened for the purposes of ESA. If a species is listed as threatened, it is likely to become endangered within the foreseeable future. If a species is listed as endangered, it is in danger of extinction throughout all or a significant portion of its range. Under the ESA, species may be listed as either endangered or threatened. The USFWS has primary responsibility for terrestrial and freshwater species, while the NMFS has responsibility over marine wildlife and anadromous fish. The Endangered Species Act is administered by two agencies, the United States Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS). The Endangered Species Act (ESA) was passed by congress in 1973 with the purpose to protect and recover imperiled species and the ecosystems upon which they depend.
