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Table 1. Estimated mean length and mean annual growth increments by age for Colorado <br />squawfish in the Colorado River for ages 0-7. Mean length for Age 0 is from Snyder (1981). <br />Mean length at Age 1 is from measured lengths of fish seined near RM 54 on June 28, 1989 <br />and assumed to be 1-yr old. Mean lengths of Ages 2-7 are from measurements of fish aged <br />using scales. Insufficient captures of Age 2 fish precluded estimates of growth increments <br />between ages 1 and 2, and 2 and 3. Growth increments for fish between ages 7 and 8 were <br />not calculated because presumptive Age 8 fish could not be reliably aged. <br />Age N Mean TL (SD) <br /> (mm) (mm) <br />0 8 7.7 (0.5) <br />1 73 71.2 (13.6) <br />2 1 181.0 --- <br />3 3 232.7 (37.3) <br />4 6 314.7 (41.8) <br />5 19 376.2 (33.3) <br />6 10 424.1 (30.6) <br />7 7 456.3 (20.0) <br />Growth period Growth increment (SD) <br />(Age) (mm) (mm) <br />0-1 63.5 (13.6) <br />1-2 --- --- <br />2-3 --- --- <br />3-4 82.0 (56.0) <br />4-5 61.5 (53.4) <br />5-6 47.9 (45.3) <br />6-7 32.2 (36.6) <br />Table 2. Estimated annual growth increments for Colorado squawfish z 400 mm TL in the <br />Colorado River. Mean increments are from measured changes in length of recaptured fish. <br />Length class is of fish at first capture. Growth increments with the same letter are not <br />significantly different (ANOVA, df= 7, 94, F = 12.87, P < 0.0001; Fisher's LSD, P < 0.05). <br />The combined average growth increment for fish 550 to 899 mm TL is also shown because <br />mean growth increments of these sizes were not statistically different. <br />Length Class N Mean growth (SD) <br />(mm) (mm) (mm) <br />400-449 6 42.7a (8.1) <br />450-499 17 30.1b (18.9) <br />500-549 20 22.2° (13.7) <br />550-599 27 9.7d (8.0) <br />600-649 16 6.4d (6.4) <br />650-700 6 11.1d (8.7) <br />700-799 4 15.0°d (4.7) <br />800-899 6 3.9d (3.0) <br />550-899 <br />59 <br />8.7 (7.4) <br />A-9