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2. Physical Habitat a. Water Ouality-CHLP is hydraulically connected to the river. It appears ground water upwells at the pond's greatest depth and helps to circulate and maintain good water quality. The water gradient flows from the river through CHLP toward Pretty Water following the historic course ofthe river. Surface water temperatures did reach 340C this summer, however, diel temperature cycles of 3-40C combined with river influx helps to suppress thermal and chemical stratification. This circulation maintains sufficient dissolved oxygen in nearly 95% of the ponds volume. b. Cover Complexity-The pond affords native fish ample cover in the form of seasonal (vegetative) and permanent (rip-raplbeaver cavities) structure and depth (>3 m). Cover provides protection from predators and thermal protection from the sun. c. Water Depth-Water depth fluctuates seasonally due to river elevation. Summer depths reach 3.4 m compared to just 2+ m during winter months. The concentration of fish at depth during summer months suggests this additional depth may provide a thermal refuge (<31 OC). d. Spawning Habitat-Substrate conditions provide a wide range of particle sizes and materials, some being successfully used by spawners. Razorback suckers are using graveVcobble substrate at the river levee's toe (> 1.5m depth) and bonytail are using small (2-5 em) cobble located (0.1 - 1.0 m depth) on the river levee. 3. Relative Size and Location The small size and steep banks of the pond make it less attractive to predatory birds, compared to broader, shallower habitats found nearby. The pond is located in a relatively isolated area, which reduces human use and bait bucket introductions. The pond also has a higher bank cover to pond volume ratio. CHLP has provided bony tail and razorback sucker a habitat where they have sustained a natural population for nearly a decade. Colonization by largemouth bass was unfortunate, but quite frankly inevitable. As pointed out by Minckley et al. (2003), these communities are temporary and must be managed accordingly. At CHLP, it appears that natural recruitment occurred in 11 of the past 12 years for bonytail (since 1994) and in at least 5 of the 12 years for razorbacks. Compared to any other conservation or recovery action in the Colorado River basin, this is simply remarkable. Management Plan for CHLP- The discovery that largemouth bass had successfully spawned in CHLP signifies the eventual failure of native recruitment. Native fish recruitment will simply cease when predator numbers reach a certain threshold that exceeds native fish production. We anticipate that will be soon; within 1 to 3 years, depending on how rapidly the bass population 19