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<br />20 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Table 8. Geometric mean CPE for varying backwater depths during all fall and spring sampling in Green <br /> River Reach 3, 1987-1992 <br /> BACKWATER SAMPLING NUMBER OF GEO. CPE PERCENT <br /> DEPTH PERIOD BACKWATERS (Age-0/1oom2) DECREASE <br /> Backwaters Fall 53 2.97 (3.85) <br /> < 1.0 ft Spring 30 0.52 (1.36) 82% <br /> Backwaters Fall 255 6.61 (6.42) <br /> I-2ft Spring 179 2.94 (4.90) 56% <br /> Backwaters Fall 68 8.12 (5.00) <br /> 2-3ft Spring 71 4.69 (5.99) 42% <br /> Backwaters Fall 24 12.46 (8.08) <br /> 3-4ft Spring 33 6.24 (3.57) 50% <br /> Backwaters Fall 38 9.17 (5.64) <br /> > 4.0 ft Spring 20 7.76 (4.01) 15% <br /> <br />Data from Reach 3 suggests that the depth of a backwater may be an important factor influencing the <br />overwinter survival of age-O squawfish. Perhaps deeper backwaters are less susceptible to freezing, and <br />mortality is lower because young squawfish are not forced into the mainchanne1. Figure 4 shows survivorship <br />from fall to spring for increasing backwater depths. These data show a inverse relationship between overwinter <br />decreases in CPE and backwater depth. Relationships between other habitat parameters and overwinter <br />decreases are still under investigation. <br />