02-22-2004, 01:13 AM
[font "Arial"][size 4]Razorback Sucker (Xyrauchen texanus)[/size][/font]
![[Image: Rzrbkskr.jpg]](http://southwest.fws.gov/fishery/images/Rzrbkskr.jpg)
[left]The razorback sucker has a long, high, sharp-edged hump, or keel, behind the head from which its name is derived. The head and body are dark, especially on breeding males and the sides brownish fading to a yellowish white abdomen. The dorsal fin is dark, the anal fins yellowish, and the caudal fins yellowish brown. The razorback sucker grows to a large size, reaching lengths of 36 to 39 inches and weights up to 12 pounds. It was listed as endangered by the U.S. Fish and Wildlife Service on October 23, 1991 (56 FR 54957).[/left] [left]The razorback sucker occurred in medium to large rivers with swift turbulent waters but also with slow backwater areas where it feeds on benthic fauna and flora, detritus, and plankton. The Razorback sucker historically was found throughout the Colorado River Basin of Wyoming, Colorado, Utah, Nevada, Arizona and New Mexico. Most wild fish are now found in Lake Mohave, which represents the largest population within the lower basin. A few adults have also been found in Lake Mead and Lake Havasu. In the upper basin, they can be found in unimpounded waters of the Green, Yampa, and mainstem of the Colorado. although adults reproduce in the reservoirs, young do not survive due to a lack of suitable food items and predation by non-native fishes.[/left]
This species declined due to habitat alterations, primarily impoundments and competition with and predation by non-native fishes. Captive populations are being maintained at Dexter National Fish Hatchery and Technology Center in Dexter, New Mexico, and at Willow Beach National Fish Hatchery, Willow Beach, Arizona. It is also being reared at Arizona's Bubbling Ponds facility near Cornville.
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[left]The razorback sucker has a long, high, sharp-edged hump, or keel, behind the head from which its name is derived. The head and body are dark, especially on breeding males and the sides brownish fading to a yellowish white abdomen. The dorsal fin is dark, the anal fins yellowish, and the caudal fins yellowish brown. The razorback sucker grows to a large size, reaching lengths of 36 to 39 inches and weights up to 12 pounds. It was listed as endangered by the U.S. Fish and Wildlife Service on October 23, 1991 (56 FR 54957).[/left] [left]The razorback sucker occurred in medium to large rivers with swift turbulent waters but also with slow backwater areas where it feeds on benthic fauna and flora, detritus, and plankton. The Razorback sucker historically was found throughout the Colorado River Basin of Wyoming, Colorado, Utah, Nevada, Arizona and New Mexico. Most wild fish are now found in Lake Mohave, which represents the largest population within the lower basin. A few adults have also been found in Lake Mead and Lake Havasu. In the upper basin, they can be found in unimpounded waters of the Green, Yampa, and mainstem of the Colorado. although adults reproduce in the reservoirs, young do not survive due to a lack of suitable food items and predation by non-native fishes.[/left] This species declined due to habitat alterations, primarily impoundments and competition with and predation by non-native fishes. Captive populations are being maintained at Dexter National Fish Hatchery and Technology Center in Dexter, New Mexico, and at Willow Beach National Fish Hatchery, Willow Beach, Arizona. It is also being reared at Arizona's Bubbling Ponds facility near Cornville.
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