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.. '0. , ':) (.;) '. .' -..:! -.J C. Category 1 candidate species within the action area: None IV. Geographic area or station name and action: Experimental stocking of razorback sucker at the Hogback Diversion Dam by Fish and Wildlife Service, Region 6. Location (attach map): A. County and State: San Juan County, New Mexico V. B. Section, township, and range (or latitude and Jongitude): C. Distance (miles) and direction to nearest town: Shiprock, New Mexico to Bluff, Utah VI. Description of proposed action: The following is a summary of the proposed action, for further details see attached research proposal. Razorback sucker are native to the San Juan River. At present this species is extremely rare in the San Juan. In order to gain information on winter habitat use, differential overwinter sUl"vival of stocked fish during varying winter base flows, contaminants uptake. and retention of razorback sucker in the San Juan River in response to experimental water releases from Navajo Dam, it is considered necessary to experimentally stock a small number of fish to add to the numbers stocked in 1994 and 1995. Forty of 704 stocked razorback sucker have been recaptured, ranging from Hogback Diversion to river mile 38.1 below Mexican Hat, Utah. The information obtained from this effort should help provide recommendations to guide future augmentation efforts and ultimately aid in the recovery of razorback sucker in the San Juan River. Eight adult razorback sucker from the San Juan River arm of Lake Powell were spawned at Ouray National Fish Hatchery in the spring of 1992. Most of the offspring from those paired matings were kept as refugia stock. The excess offspring, above and beyond refugia needs, were experimentally stocked in the spring and fall of 1994 and the fall of 1995. Currently 1650 F1 juvenile razorback sucker are being reared at Wahweap ponds (Utah Division of Wildlife Resources) near Lake Powell. All fish to be stocked are currently PIT-tagged. Fish would be weighed, measured, checked for general health. Ten fish would be surgically implanted with an AVM, 13-month radio transmitter prior to stocking. Surgically implanted fish would be held in separate enclosures and closely monitored. This will allow for implantation of a radio transmitter into another fish should a mortality occur. In late September 1996, 300 fish, including the ten radio-tagged fish, would be stocked at river mile 158.6. Stocking at this upper-most of the four original sites should allow for retention in the river system even atter the downstream dis.placements associated with post- stocking stress.