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<br />List of Tables <br /> <br />Table 1. Age (in years), mean total length (mm), and estimated wild annual survival rates for <br />humpback chub. Data provided by C. Walters. ....................................................................26 <br /> <br />Table 2. Predicted numbers of humpback chub using Age Structured Mark-Recapture modeling <br />that would need to be removed at age-O, grown in captivity to 171 mm and released into the <br />wild in order to stabilize the abundance of age-4+ fish at the level estimated in 2000 (arrest <br />further decline) and to increase the abundance of age-4+ fish back to levels estimated in <br />1990 (effect a positive population response). ....................................................................... 29 <br /> <br />Table 3. Fall point population estimates of humpback chub> 150 mm in Little Colorado River. <br />1991 & 1992 estimates are from Douglas and Marsh (1996); 2000 estimateis from Coggins <br />and Van Haverbeke (2001); 2001 estimate is from Van Haverbeke and Coggins (2003), <br />2002 estimate is from Van Haverbeke (2003), and 2003 estimate is from Van Haverbeke <br /> <br />(2004). ..................... ............... .............. ..... ................... ................... ............ .......................... 32 <br /> <br />Table 4. Summarized risks and benefits associated with various potential management actions. <br /> <br />...............................................................................................................................................48 <br /> <br />list of Figures <br /> <br />Figure 1. Early photograph of humpback chub taken on the mains tern Colorado River, a short <br />distance upriver from Bright Angel Creek. Photograph from Grand Canyon Archive, Rust <br /> <br />Collection. .....................................................................................................................,........ . 9 <br /> <br />Figure 2. Daily mean discharge (cubic feet per second) of Little Colorado River for water years <br />1947-2003. Data from USGS gage station 0940200 near Cameron, Arizona. .................... 21 <br /> <br />Figure 3. Provisional estimated and projected humpback chub population (Little Colorado River <br />[LCR] stock) in Grand Canyon, assuming recruitment remains at mid 1990s level. This <br />example figure of the base Age Structured Mark-Recapture model depicts the predicted <br />effect of capturing 1,350 age-O humpback chub per year from the LCR, growing them in <br />captivity to 171 mm, and beginning release in 2005. The model predicts that by the year <br />2020, abundance estimates of age-4+ fish would equal the abundance estimated to be <br />present in the year 2000. ....................................................................................................... 30 <br /> <br />4 <br />