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<br />Table l. Current humpback chub population estimates with confidence intervals. <br /> <br />Population Year Estimate Confidence Interval Author/Method <br />Yampa Canyon 1998- 400 100-2000 B. Haines & T. <br /> 2000 Modde, Likelihood <br /> Density Function <br />Desolation/Gray 2001 1,254* 733-2,697* J. Jackson et aL <br />canyons 2002 2,612* 1,477-8,509* Closed Mark- <br /> 2003 937* 636-1,520*t Recapture <br />Black Rocks 1998 764 512-1,206 C. McAda, Closed <br /> 1999 921 723-1,208 Mark-Recapture <br /> 2000 539 223-1,497 <br /> 2003 500* 221-1,176* <br />Westwater Canyon 1998 4,744 37,60-14,665 J. Jackson, Closed <br /> 1999 2,215 1,608-7,508 Mark-Recapture <br /> 2000 2,201 1,335--4,124 <br /> 2003 2,413* 1,500--4,396. <br />Cataract Canyon 2003 150. 71--407. P. Badame, et aI., <br /> Closed Mark- <br /> Recapture <br />Grand Canyon 2004 2,000--4,000 L. Coggins, Age <br /> Structure-Mark <br /> Recapture <br /> <br />· Preliminary data. <br />t Sampling season switched to fall from summer. <br /> <br />The recovery goals for humpback chub (U.S. Fish and Wildlife Service 2002) discuss the concept <br />of redundancy and core populations: <br /> <br />"Humpback chub occur as multiple, demographically independent populations in widely <br />distributed regions of the Colorado River Basin; distances of 17-394 kIn separate adjacent <br />populations. This widely clumped distribution pattern contributes to redundancy as species <br />protection against threats and catastrophic events. Thc five populations in the upper basin occur <br />in discrete regions of three subbasins, including three populations in the Colorado River, and one <br />population each in the Green River and Yampa River. The lower basin population in Grand <br />Canyon exists independently downstream of Glen Canyon Dam, where it has been <br />geographically isolated from upper basin populations since dam construction in 1963. This <br />pattern of geographic separation among all six populations provides population redundancy and <br />greatly reduces the likelihood of a catastrophic event simultaneously affecling the majority of <br />populations. <br /> <br />DRAFT HBC Genetics Management Plan-2 <br /> <br />00648 <br />