2004-06-29_PERMIT FILE - C1981038 (3)

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13 were collected in the lower Green River near Hell Roaring Canyon (Gutermuth et al. 1994). Juveniles razorback suckers have been collected in recent }-ears from Old Chazley Vv ash, a wetland adjacent to the Green River (Modde 1996). Between 1992 and 1995 larval razorback suckers were collected in the middle and lower Green River and within the Colorado River inflow to Lake Powell (Muth 1995). The current range of the razorback sucker in the Colorado River extends upstream to Rifle, Colorado. Most razorback suckers captured in the Grand Valley area have been located in flooded gravel-pit ponds adjacent to the river. However, Osmundson and Kaeding (1989) documented razorback sucker movement in various river habitats in the Grand Valley azea. Additional surveys since 1988 have documented razorback suckers in riverside ponds as faz upstream as river mile 235 near Rifle, Colorado (Burdick 1992). Humpback Chub The humpback chub is endemic to the Colorado River Basin and is part of a native fish fauna traced to the Miocene epoch in fossil records (Miller 1958; Minckley et al. 1986). Humpback chub remains have been dated to about 4000 B.C., but the fish was not described as a species until the 1940's (Miller 1946), presumably because of its restricted distribution in remote white water canyons (USFWS 19906). Because of this, its original distribution is not known. Until the 1950's, the humpback chub was known only from Grand Canyon. During surveys in the 1950's and 1960's humpback chub were found in the upper Green River including specim: ns from Echo Park, Island Pazk, and Swallow Canyon (Smith 1960, Vanicek et al. 1970). Individuals were also reported from the lower Yampa River (Holden and Stalnaker 19756), the White River in Utah (Sigler and Miller 1963), Desolation Canyon of the Green River (Holden and Stalnaker 1970) and the Colorado River neaz Moab (Sigler and Miller 1963). Today the lazgest populations of this species occur in the Little Colorado and Colorado rivers in the Grand Canyon,-and in the Black Rocks azea of the Colorado River. Other populations have been reported in Westwater and De Beque Canyons of the Colorado River, Desolation and Gray Canyons of the Green River, Yampa and Whirlpool Canyons in Dinosaur National Monument (USFWS 19906). One individual w•as recently captured in the Gunnison River (Burdick 1995). Little is known about the specific spawning requirements of the humpback chub. It is known that the fish spawn soon after the highest spring flows when water temperatures approach 68 ° F (Kaeding et al. 1990; Karp and Tyus 1989; USFWS 19906). The collection of ripe and spent fish indicated that spawning occurred in Black Rocks during June 2-15, 1930, at water temperatures of 53 ° to 61 ° F; in 1981, spawning occurred Vtay 1 ~-25, at water temperatures of 61 °-61.7° F (Valdez et al. 1982). Humpback c`:ub spawned in Black Rocks on the Colorado River in 1983 when maximum daily water temperatures were » ° to 63 ° (Archer et al. 1985).