Laserfiche WebLink
<br />2 <br /> <br />population is probably somewhere between 2,000 and 4,000 age-4 and older fish. A <br />different estimate, using the "Supertag" assessment model, resulted in an estimate of <br />1,100-1,200 adults in 2001. Estimates of the LCR spawning population for 1992-1995 <br />were 2,000-4,700 adults (Douglas and Marsh 1996). The assessment model also <br />determined a lower level of recruitment (i.e., fish reaching maturity at age-4) over the last <br />decade. The GCMRC report also stated that if recruitment continues to be stable at an <br />average of the 1995-98 rate, the population will likely stabilize at 1,000-3,000 adults. <br /> <br />2.2 Status of Humpback Chub Populations in the Upper Colorado River Basin <br /> <br />There are currently six self-sustaining populations of humpback chub in the <br />Colorado River Basin, including one in Grand Canyon and five in the upper basin. The <br />six populations are in the following locations and their approximate numbers are as <br />follows: <br /> <br />1. Yampa Canyon: Population small, about 400, based on model using <br />1998-2000 data (l-Iaines and Modde 2002). Effort is being expanded in <br />2003 to develop a more precise estimate. <br />2. Desolation/Gray Canyon: Estimates from 2001 and 2002 were 1,500 and <br />1,700, respectively (Hudson and Jackson 2003a). <br />3. Black Rocks Canyon: About 1,000 (McAda 2002). <br />4, Westwater Canyon: 2,200-4,700 based on 3 sampling sites in 1998-2000 <br />(Hudson and Jackson 2003b); effort is being expanded in 2003. <br />5. Cataract Canyon: About 500 (Valdez 2002); a mark-recapture effort will <br />be investigated in 2003 (this effOlt was scheduled to begin in 2002 but was <br />postponed due to low flows). <br />6. Grand Canyon: Between 2,000 and 4000 (GCMRC 2003). <br /> <br />Recovery goals exist for the humpback chub in the Colorado River Basin, and <br />include all six populations (U.S. Fish and Wildlife Service 2002). They provide guidance <br />on recovery of the species, basin-wide, and identify site-specific management actions, <br />and objective, measurable criteria for achieving recovery. The Recovery Goals identify <br />actions necessary to conserve and recover the Grand Canyon population of humpback <br />chub, as well as the role of the Grand Canyon population in recovery of the species. They <br />were used by the Ad Hoc Committee in the development of this comprehensive plan. <br /> <br />In regard to developing the proposals attached to this report, a need was identified <br />for a coordinated effort to develop broad nonnative fish stocking procedures. The <br />UCRRP developed procedures in the mid-1990s with goals potentially similar to these <br />needs in mind (see Section 2.3). Also, a Recovery goal that is not identified in any of the <br />current attached proposed projects is under Factor D - Adequate regulatory mechanisms: <br />#9. mechanisms determined for legal protection of adequate habitat in mainstem <br />Colorado River through the Grand Canyon and the Little Colorado River. This may be <br />determined later, and much of it is probably already under Federal lands or could be <br />included in future conservation plans that also need to be developed under Factor D. <br />