Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for Big Creek Crayfish and St. Francis River Crayfish and Designation of Critical Habitat

We, the U.S. Fish and Wildlife Service (Service), determine threatened species status under the Endangered Species Act of 1973 (Act), as amended, for the Big Creek crayfish (Faxonius peruncus) and the St. Francis River crayfish (Faxonius quadruncus), two crayfish species from southern Missouri. We also finalize a rule under the authority of section 4(d) of the Act that provides regulatory measures that are necessary and advisable to provide for the conservation of these species. In addition, we designate critical habitat for the species; in total, approximately 1,069 river miles (1,720 river kilometers) for the Big Creek crayfish and 1,043 river miles (1,679 river kilometers) for the St. Francis River crayfish in Iron, Madison, St. Francois, Washington, and Wayne Counties, Missouri, fall within the boundaries of the critical habitat designations. This rule applies the protections of the Act to these species and their designated critical habitats.