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<br />..<
<br />
<br />Table 3. Total lengths and weights of larval bony tail chub
<br />cultured in a recirculating system at Willow Beach (Arizona)
<br />National Fish Hatchery, 1981.
<br />
<br />Age Total length (mm) Weight (mg)
<br />(days) Meana Range Meana Range
<br />Ob: 6.8 6.7- 6.9 2.8 2.3- 3.4
<br />7 8.2 7.3- 9.1 3.6 2.8- 4.5
<br />14 9.7 8.4-12.6 6.4 4.6- 14.4
<br />21 11.5 10.2-14.1 8.7 5.7- 16.8
<br />28 18.1 16.3-20.1 48.0 33.1- 70.7
<br />35 20.2 19.1-21.6 76.4 62.8. 89.0
<br />42 31.1 26.7-35.9 278.2 179.4- 397.3
<br />49 36.1 30.643.9 448.7 253.3- 746.2
<br />56 38.8 33.3-46.7 692.8 ~41.8- 839.9
<br />63 43.6 36.7-47.8 740.7 466.I~ 910.3
<br />70 49.5 42.9-54.3 974.6 714.1-1,326.8
<br />
<br />aMean total length and weight of 10 fISh per sample.
<br />b Age of newly hatched larvae.
<br />
<br />(Table 2), the optimum temperature for reproduction is
<br />believed to be 20-21 oc.
<br />The decline of the bonytail chub has been correlated with
<br />the construction of dams which created cold downstream
<br />water temperatures, reductions in water flow, and loss of
<br />habitat (Joseph et al. 1977; Smith et al. 1979). The 960/0
<br />mortaIity of eggs incubated at cold water temperatures
<br />supports this theory of dam-related decline. Another reason
<br />for the decline of the bonytail chub is the possibility of
<br />hybridization between the roundtail chub (Gila robusta) and
<br />humpback chub (Gila cypha) in the upper Colorado River
<br />(Holden and Stalnaker 1970; Mincldey 1973). It is apparent
<br />that all three species are capable of hybridizing, because Fl
<br />generations of the bon)rtail X roundtail chub and bonytail X
<br />humpback chub have been produced in a hatchery (Hamman
<br />1981).
<br />The future of the bonytail chub may depend on hatchery
<br />propagation to help restore the species. In addition to pro-
<br />viding specimens for restocking of selected fonnerhabitats
<br />and supplementing current populations, these culture efforts
<br />prOvide an opportunity to study the fISh under hatchery
<br />conditions. Based on captive and cultured specimens, much is
<br />being learned about their reproduction, early life history, and
<br />preferences. This information may be necessary to insure the
<br />survival of the species.
<br />
<br />Acknowledgments
<br />
<br />I thank Lyle Miller, Peter Carboni, Joe Saenz. and the staff
<br />at Willow Beach National FISh Hatchery for assistance during
<br />this study, and TheophiIus Inslee, Buddy Jensen, J. Mayo
<br />Martin, John Mazuranich, }oseph . McCraren, William
<br />Miller, and Robert Piper for reviewing the manuscript.
<br />
<br />References
<br />
<br />Allison, R. 1957. Some new results in the treatment of ponds to
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<br />Ball, R.C., and E.H. Bacon. 1954. Use of pituitary materials in the
<br />propagation of minnows. Prog. Fish-Cult. 16:108-113.
<br />Behnke, R.J., and D.E. Benson. 1980. Endangered and threatened
<br />fishes of the upper Colorado River basin. Colorado State Uni-
<br />versity, Fort Collins. Coop. Ext. SeJV. Bull. 503A. 34 pp.
<br />Billard, R. 1977. A new technique of artificial insemination for
<br />salmonids using sperm diluent. Fisheries (Am. Fish. Soc.)
<br />2(1):24-25.
<br />Clemens, H.P., and K.E. Sneed. 1962. Bioassay and use of pitui-
<br />tary materials to spawn warm-water fish. U.S. Fish Wildt. Servo
<br />Res. Rep. 61. 30 pp.
<br />Cope, E.D., and H.C. Yarrow. 1875. Report upon the collection
<br />of fIShes made in portions of Nevada, Utah, California, Colo-
<br />rado, New Mexico and Arizona during the years. 1871, 1872,
<br />1873, and 1874. Rep. Geogr. Geot. Surv. W. lOOth Meridian
<br />(Wheeler Survey) 5 (Zoology):635-703.
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<br />1979. Fishes of North America endangered, threatened, or of
<br />special concern: 1979. Fisheries (Am. FISh. Soc.) 4(2):29-44.
<br />Hamman, R.L. 1981. Hybridization of three species of chub in a
<br />hatchery. Prog. Fish-Cult. 43:140-141.
<br />Holden, P.B., and C.B. Stalnaker. 1970. Systematic studies of the
<br />cyprinid genus Gila, in the upper Colorado River basin,
<br />1967-1973. Copeia 1970 (3):409-420.
<br />Jonez, A., and R.C. Sumner. 1954. Lakes Mead and Mohave
<br />investigation, a comparative study of an established reservoir as
<br />related to a newly created impoundment. Nev. Fish Game,
<br />Reno. 186 pp.
<br />Joseph, T. W., J.A. Sinning, R.J. Behnke, and P.B. Holden. 1977.
<br />An evaluation of the status, life history, and habitat require-
<br />ments of endangered fishes of the upper Colorado River system.
<br />West. Energy Land Use Team, U.S. FISh Wildl. Serv., Fort
<br />Collins, Colo. FWSlOBS-77162.183 pp.
<br />Leitritz, E. 1960. Trout and salmon culture. Calif. Dep. Fish
<br />Game. FISh. Bull. 107. 169 pp.
<br />Minckley, W.L. 1973. Fishes of Arizona. Ariz. Game Fish Dep.,
<br />Phoenix. 293 pp.
<br />Smith, O.R., R.R. Miller, and W.D. Sable. 1979. Species relation-
<br />ships among fIShes of the genus Gila in the upper Colorado
<br />River drainage. Proc. First Coof. Sci. Res. in Nat!. Parks. Nat!.
<br />Park Servo 1:613-623.
<br />U.S. Department of the Interior. 1980. Federal Register. U.S. Fish
<br />Wildl. Serv., Washington, D.C. Part II, 45(99):33768-33781.
<br />U.S. Fish and Wildlife Service. 1979. Hwnpback chub recovery
<br />plan. Denver, Colo, 70 pp.
<br />Vanicek, C.D., and R.H. Kramer. 1969. Ufe history of the Colo-
<br />rado squawflSh, Ptychocheilus lucius, and the Colorado chub,
<br />Gila robusta, in the Oreen River in Dinosaur National Monu-
<br />ment, 1964-1966. Trans. Am. FISh. Soc. 98:193-208.
<br />
<br />Accepted 2 April/982
<br />
<br />'"
<br />
<br />Prog. Fish-Cult. 44(4), October 1982
<br />
<br />203
<br />
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