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. . . A variety of fish culture techniques have been used on the four species of Colorado River endangered fish since 1974. The following is a summary of past culture and propagation techniques used on each of the four species of fish (Tables 2.3, 2.4, 2.5 and 2.6). These techniques are presented for each of the developmental stages, including egg procural, egg incubation, swim-up fry, fry (Phase I), fingerling (Phase II), and fingerling (Phase III). Colorado Squawfish A summary of culture efforts for Colorado squawfish is presented in Table 2.3. Both human chorionic gonadotropin (HCG) and carp pituitary (CP) have been used as hormones to induce timely ovulation of females (Table 2.3a). Toney (1974) injected HCG intraperitoneally at a rate of 900 Lu.jlb and found eggs in the gravel raceway 1 week later as a result of natural spawning by wild fish. Hamman (1981a) injected acetone-dried CP at rates of 4 mgjkg and 8 mgjkg of body weight and nearly doubled egg production of wild females (injected = 55,000 eggs vs. uninjected = 25,000 eggs). Jensen (1983b) used CP (2 mgjlb) on females and HCG on males (150 Lu.jlb). Hamman (1986) used acetone-dried CP on 9 and 10-year old fish at a rate of 4 mgjkg. These fish ovulated in 18 - 20 hours and 20 - 24 hours, and produced an average of 77,400 and 66,185 eggs per female, respectively. Hamman (1989) also injected wild females with CP and obtained an average of 82,576 eggs per female. The Arizona Game & Fish Department (AGF 1988, 1989) injected females with CP at a rate of 150 Lu.jlb and produced averages of 29,946 and 39,130 eggs per female. Hamman (1981a) incubated eggs at 22 - 240C, 20 - 2eC, and 12 - 130C with 67, 59, and 30% hatching success, respectively (Table 2.3b). Hatching times at these temperatures were 90 - 130 hours, 90 - 120 hours, and 145 - 180 hours, respectively. Jensen (1983a) reported 59% hatching success with eggs held in Heath Trays and 66% with eggs held in McDonald Jars. Hamman (1986) found that eggs held at the same temperature (20 - 220C) and the same flow rate (15 - 23ljmin) exhibited similar hatching times of 100 - 144 hours for 9-year old females and 96 - 144 hours for 10-year old females. Fourteen-hour eggs incubated at Colorado State University (CSU) (1989) at 210C hatched in 80 - 110 hours (total incubation time of 94-124 hours) while eggs incubated at 11.40C died and disintegrated. AGF (1988, 1989) reported hatching times of 48-72 hours at 680F (200C). 2.2 - 2