Xyraucben texanus, (Abbott, 1860)
Razor back chubs can live for more than 40 years and weigh up to 14 lbs. (6.4 kg).
SIZE: The common length for the razorback sucker is 50 cm (19.7 in) with a maximum reported length of 91 cm (36 in).
RANGE: Razorback chub were historically found throughout the Colorado River drainage basin but now have become rare above the Grand Canyon. These fish are now restricted to a relatively small number of sites in the Colorado River system from Wyoming to southeastern California. In the upper river basin of the Colorado River, the largest surviving razorback chub populations are found in the Green and Yampa Rivers. The largest population of razorback chub can be found in Lake Mohave, Arizona.
HABITAT: Razorback suckers prefer to live over sand mud, or gravel bottoms. They can inhabit a diversity of habitats from mainstream channels to the backwaters of medium and large streams of rivers. The razorback sucker spends most of its life at depths where ultraviolet light cannot penetrate but these fish will move into the shallows to spawn.
DIET: Razorback suckers feed on algae, plankton, plant matter, small aquatic invertebrates and detritus.
The razorback sucker is a native species of the Colorado River dating back to more than 3 million years ago. Male and female suckers mature and can reproduce at three to four years of age.
Spawning occurs in late winter or spring. Razorback sucker spawning behavior usually includes a single female being followed by multiple males. The entire group of razorback suckers will then settle down to the water bottom and the females will extrude their eggs and the males will simultaneously extrude their milt to fertilize the eggs. The female suckers will then spawn multiple times with several males.
Razorback sucker eggs will not survive in temperatures less than 50 degrees Fahrenheit (10 degrees Celsius).
The razorback sucker was listed as Protected under Utah law in 1973, listed as Endangered under Colorado law in 1979, and was classified as Endangered under the Endangered Species Act and given full protection under the law in 1991.
Today, all populations of razorback suckers are supplemented with stocked fish except for the Lake Mead population. The Lake Mead and Mohave populations are the only populations comprised of wild fish.
Restoration actions being taken to restore razorback sucker populations include managing water flows to insure minimum in-stream flows are maintained in razorback sucker habitats, constructing fish passages and screens at dams to provide access to hundreds of miles of critical razorback sucker habitat, restoring razorback floodplain habitat, monitoring and assessing razorback sucker population numbers, managing non-native and invasive species that might have negative impacts on razorback sucker populations and attempting to re-establish naturally self-sustaining populations of razorback sucker populations through propagation and stocking.