Critically Endangered
Razorback sucker
Xyrauchen texanus
The razorback sucker is a suckerfish found in rivers and lakes in the southwestern United States and formerly northwestern Mexico.
Appearance
The razorback sucker is most notable for the sharp-edged bulge on the anterior part of its back, between the head and dorsal fin, giving rise to its common name, as well as to the alternative name "humpback sucker". The fish has an olivaceous to brown-black color on top grading to a lighter yellow below. Adult razorbacks are easily distinguished from other suckers by the predorsal keel.
The fish can attain lengths of up to 91 cm (3 ft) and weights of 6 kg (13.2 lb).
Range and habitat
The species originally occurred throughout the medium-sized and large rivers of the Colorado River Basin, among them to the states of Baja California and Sonora in Mexico, but its range has shrunk to the river above the Grand Canyon, and to Lake Mead, Lake Mohave, and Lake Havasu on the lower part of the river. The reason for the decline is largely due to habitat loss. A population of over 3,000 fish in Lake Mohave has been created by an augmentation program using fry that were produced naturally in the lake.
It has been a federally protected fish since 1991 and is rated as "Critically Endangered" by the International Union for Conservation of Nature, and Critically Imperiled by NatureServe.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Breeding
It usually moves from deep water to suitable spawning grounds to breed, and research into its habits and breeding locations is ongoing.
In crisis
It used to inhabit much of the Colorado River Basin but commercial fishing, river damming, and habitat loss have caused great declines in populations. There are some signs of recovery, with fish being observed in the lower Grand Canyon in 2012 and 2013. The largest and most genetically diverse population is found in Lake Mohave, Arizona/Nevada border.
Subsequent encounters of fish tagged while emigrating from wetlands have documented limited recruitment to the adult population by wild spawned razorback sucker. In 2021, the Fish and Wildlife Service proposed to reclassify the razorback sucker as threatened, rather than endangered, under the Endangered Species Act.
Razorback sucker is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Razorback sucker, Wikidata item Q1943923. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
