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1 <br />1 <br /> <br /> <br /> <br /> <br /> <br /> <br />H <br />P <br /> <br /> <br /> <br /> <br />11 <br /> <br /> <br /> <br /> <br />Land Ownership/Management Agencies: The National Park Service (Lake <br />Mead National Recreation Area and Grand Canyon National Park) has <br />broad resource management responsibilities within the boundaries of the <br />National Recreational Area. The Hualapai Tribe also has management <br />interests in this reach. Water levels of Lake Mead are controlled by <br />USBR, Boulder City, Nevada. Nevada Department of Wildlife and AGFD <br />are the leads for fish and wildlife management, in coordination other <br />management agencies. <br />Species/Critical Habitat Present: Razorback sucker is present with critical <br />habitat designated in the reach (USFWS 1994a). A humpback chub has <br />recently been taken in the upper reservoir. Colorado pikeminnow and <br />bonytail are extirpated from this subunit. <br />Razorback Sucker <br />Current Status and Recovery Efforts: A large population of razorback <br />sucker was present in Lake Mead until the 1960s, but was not found <br />during sampling efforts in the 1970s (Minckley 1973, Minckley 1991). <br />Subsequent to that, NDOW and others contacted this species infrequently <br />during fishery investigations on Lake Mead. In the 1990s, two small <br />concentrations of razorback sucker were located in Las Vegas Bay and <br />Echo Bay, respectively (Abate et al. 2002, Golden and Holden 2001, <br />Holden 1994, Holden et al. 1997, Sjoberg 1995). Adult population <br />estimates for these areas ranged from 68 to 124 for Las Vegas Bay and <br />from 45 to 66 fish for Echo Bay (Abate et al. 2002). Wild larvae have also <br />been collected at the inflow of the Colorado River. Unlike other areas of <br />the lower basin, recruitment in these populations has been documented <br />by aging several fish using the pectoral rays. Three fish were aged at 10 <br />years or less, three ranged from 10 to 15 years of age, nine ranged from <br />16-20 years and four were > than 20 years old, including one fish that was <br />near 35 years of age. One 40.7 cm subadult was aged at 6 years (Abate <br />et al. 2002). Radio-telemetry studies have also been conducted by <br />BIO/WEST with funding provided by SNWA and USBR. Small numbers <br />18 <br />