The proposed critical habitat designation includes approximately 1,068 river miles in the four states, including portions of the Cimarron River and the Ninnescah River in Kansas.

The agency on Tuesday published the proposal in the Federal Register. The proposal says the fish, once found in each of the four states and in Colorado, is now found only in one river from New Mexico into Texas and rivers in Kansas and Oklahoma must also be protected to ensure they could be relocated, if necessary, to prevent extinction.