2010-11-22_REVISION - M2009023 (7)

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(Lentsch et al. 1996). Monitoring in late 1996 and 1997 found these fish scattered in suitable habitats from just below the upstream stocking site at Shiprock, New Mexico, to Lake Powell. During the fall of 1997, the fish stocked in 1996 were caught in relatively high numbers and exhibited good growth rates as well as good survival rates (Holden and Masslich 1997). In August 1997, an additional 100,000 young-of-year Colorado pikeminnow were stocked in the river. In October 1997, the young-of-year stocked two months previously were found distributed below stocking sites and relatively large numbers also nearly 10 miles above the Shiprock stocking location. The 1997 stocked fish were smaller than those stocked in 1996, but apparently could move about the river to find suitable habitats (Holden and Masslich 1997). In July 1998, an additional 10,571 young-of-year pikeminnows were stocked at Shiprock but only one was found through March 1999 in the lower San Juan River (Archer et al 2000). Furthermore in July 1999, 500,000 larval pikeminnow were stocked just below Hogback Diversion at RM 158.6. The larvae were found 157 miles below the stocking site 62 hours later and were never recaptured again. High flows in 1999 likely washed them into Lake Powell (Jackson 2001). Due to the lack of retention in 1999, 105,000 larvae were stocked in June 2000 just below Cudei Diversion (RM 142). Despite more normal flows in 2000, only four larvae were found and three had floated 64 miles downstream in the two days since stocking. No 2090 stocked larvae were found during a sampling trip four weeks later but a pikeminnow fitting the size class of the 1999 stocking was found. During an October 2000 sampling trip three more suspected 1999 stocked pikeminnows were captured but, again, no larvae stocked in 2000 were found (Jackson 2001). Razorback Sucker Species/Critical Habitat Descriation The razorback sucker, an endemic species unique to the Colorado River Basin, was historically abundant and widely distributed within warmwater reaches throughout the Colorado River Basin. The razorback sucker is the only sucker with an abrupt sharp-edged dorsal keel behind its head. It has a large fleshy subterminal mouth that is typical of most suckers. Adults often exceed 3 kg (6 pounds) in weight and 600 mm (2 feet) in length. Historically, razorback suckers were found in the main stem Colorado River and major tributaries in Arizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming, and in Mexico (Ellis 1914; Minckley 1983). Bestgen (1990) reported that this species was once so numerous that it was commonly used as food by early settlers and, further, that commercially marketable quantities were caught in Arizona as recently as 1949. In the Upper Basin, razorback suckers were reported in the Green River to be very abundant near Green River, Utah, in the late 1800's (Jordan 1891). An account in Osmundson and Kaeding (1989) reported that residents living along the Colorado River near Clifton, Colorado, observed several thousand razorback suckers during spring runoff in the 1930s and early 1940s. In the San Juan River drainage, Platania and Young (1989) relayed anecdotal historical accounts of "humpies," thought to be razorback suckers ascending the Animas River to Durango, Colorado, around the turn of the century. A marked decline in populations of razorback suckers can be attributed to construction of dams and reservoirs, introduction of nonnative fishes, and removal of large quantities of water from . I1