The Colorado River of the American West supports a mainstream fish community that is classified as the “Big River” fishes. Four of these fishes are listed as endangered under provisions of the Endangered Species Act of 1973, as amended. Three fishes (i.e., Colorado pike minnow Ptychocheilus Lucius, humpback chub Gila cypha, and bonytail G. elegans) have been listed for over 10 years, and they have recovery plans that were prepared prior to designation of critical habitats. Recently the Colorado squawfish was renamed by the American Fisheries Society and hereafter will be refered to in this document as the Colorado pike minnow. A fourth fish, the razorback sucker Xyrauchen texanus was listed in 1991. Critical habitats for all four fishes were designated by the U.S. Fish and Wildlife Service in 1994. The listing of these four fishes, and the potential endangerment of others suggest that this large river ecosystem is at risk. When such major environmental problems exist, present policy and philosophies have resulted in the decision to consider the recovery of more than one species, and thus to prepare multispecies or ecosystem recovery plans. The razorback sucker recovery plan has been prepared in the spirit of this philosophy. In addition, the recovery plan has been drafted more as a strategic plan to allow flexibility in its implementation. Presently, recovery of the fish is being accomplished by formal recovery implementation programs conducted in important geographic areas. It is anticipated that these recovery implementation programs will develop very site-specific work plans under the broad guidance provided in the razorback sucker recovery plan.
Tyus, Harold M., "Razorback Sucker (Xyrauchen texanus) Recovery Plan" (1998). All U.S. Government Documents (Utah Regional Depository). Paper 467.