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1 ) <br />SPAWNING <br />Adult razorback suckers (Xyrauchen texanus) were captured, via <br />electroshocking, in the vicinity of the area known as Razorback Bar on the <br />Green River (RMI 311.0), 20 April through 15 May 1987. A total of 53 fish were <br />captured during these operations (Table 1). Nineteen of these fish were <br />females, 33 fish were males, and the sex in one fish was undeterminable. At <br />first capture, four of the female fish were in a non-breeding condition <br />(neither tuberculated or ripe), and 15 of the female fish were ripe (had <br />expressible sex products). Also, at first capture, four of the male fish were <br />in a non-breeding condition, 28 of the male fish were ripe, and one male fish <br />was tuberculated (but had no expressible sex products). During the operations, <br />two female and two male fish were recaptured twice (tag numbers 2260, 6254, <br />6414, 6416). Early and late in the operations, fish were stripped of sex <br />products in the field, near the location of capture. However, the majority of <br />fish were transported to a hatchery at Ouray NWR, where most of the fish <br />received hormone injections prior to stripping. The exact procedures used <br />during 1987 for fertilization of eggs are unknown (no records). <br />Table 2 summarizes the gamete crosses of razorback suckers by date, <br />number of fish involved, tag numbers, number of eggs produced, incubation <br />temperatures, date fry hatched, and number of fry that hatched. Table 3 <br />summarizes the release dates of razorback suckers by river male and tag number, <br />for fish held at Ouray NWR or released in the field. Referring to Tables 1, 2, <br />and 3, will help the reader follow the discussion. <br />Most of fish captured 23 April through 9 May, were taken to the Ouray <br />facility for hormone injections. It has been shown that spawning can be <br />induced in razorback suckers using hormone injections (Inslee 1982, Hamman <br />1985). The fish were injected intramuscularly with human chorionic