9720

• UCREFRP Catalog Number: 9720
• Author: U.S. Fish and Wildlife Service.
• Title: Razorback sucker ‎(Xyrauchen texanus)‎ genetics management and captive propagation plan, Dexter National Fish Hatchery and Technology Center.
• USFW Year: 2004.
• USFW - Doc Type: Dexter National Fish Hatchery and Technology Center
• Copyright Material: NO

added to the founding broodstock pool. In 1999, 20,000 wild caught fry and 1,050 wild caught
fingerlings (85mm) of Lake Mohave origin were transferred from Willow Beach NFH to Bounds
Pond, a U. S. Fish and Wildlife Service owned pond near Clifton, Colorado, for growout. These
fish serve a dual purpose as future broodstock and for augmentation of the San Juan River System.
In February, 2003, utilizing the "nearest neighbor" approach, the Upper Colorado River Endangered
Fish Recovery Program (UCREFRP) Biology Committee approved a strategy to incorporate the
Lake Mohave fish into the captive broodstock to increase the number of paired matings, and genetic
diversity of the existing stock (UCREFRP, Biology Committee Meeting notes, 2003). Lake
Mohave fish however, will only be used in paired matings with hatchery broodfish of upper basin
origin. Essentially, no Lake Mohave X Lake Mohave crosses will be created.
San Juan River System
Wild RBS are considered extirpated from the San Juan River mainstem. The last recorded
collection of a wild RBS in the San Juan River was in 1988 near Bluff, Utah (Ryden 2000). The
U.S. Fish and Wildlife Service initiated development of a captive broodstock for the San Juan River
from fish collected in the San Juan arm of Lake Powell in the early 1990s at the Ouray NFH, Utah.
The fish were spawned at Ouray in 1992, the eggs were hatched at the Belview Research
Laboratory, Belview, Colorado, and reared at Wahweap SFH. In the early 1990s, all adults and
offspring were transferred from Ouray NFH to ponds maintained at Wahweap SFH near Lake
Powell. In 1995, ninety RBS from the 1992 spawning effort conducted at Ouray NFH and reared at
Wahweap SFH were transferred to the Grand Valley Endangered Fish Facility and used in a
selenium toxicity study (M. Baker, FWS Pers. comm. 2002). Currently, Wahweap SFH maintains
backup broodfish lots of Green River origin; however, no captive propagation is planned at this
time. In 1994 captive reared RBS from Lake Mohave and Grand Junction stocks were the first RBS
stocked into the mainstem San Juan River by the U.S. Fish and Wildlife Service (Ryden 2000).
Production facilities that have contributed fish to the augmentation effort in this subunit are Dexter