Congress enacts the Endangered Species Act (ESA) “to provide a means whereby the ecosystems upon which endangered species and threatened species depend may be conserved.”  The ESA establishes a framework for listing species, protecting their critical habitat, requiring federal agencies to consult with the U.S. Fish & Wildlife Service and/or the National Marine Fisheries Service if their actions may affect a listed species, and prohibiting the “take” of an endangered species without a permit.