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<br />COMMUNICATIONS
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<br />TABLE I.-Survival of razorback sucker fry, subfmgerlings, and fingerlings in earthen ponds during 1985 at Dexter
<br />National Fish Hatchery, New Mexico.
<br />
<br />pood size Stocking Days in Recovery Food Perce 0 I
<br />(acres) Number of lish Size (fish/lb) pond Number of fish Size (fish/lb) conversiona survival
<br /> Fry
<br />034 33.852 71,000 76 33,206 533 98.t
<br />0.34 36.8\6 71.000 77 32,309 583 87.8
<br />0.89 93,600 71,000 78 89,058 724 95.1
<br />L08 111.932 94.000 69 110,323 508 98.6
<br /> Subfingerlings
<br />0.89 50,027 724 60 46,360 152 \.90 92.7
<br />098 50,025 674 5\ 46,389 14t 1.34 92.7
<br />0.86b 49.999 549 70 47,914 159 2.67 95.8
<br /> Fingerlings
<br />0.98 26.860 158 50 25,875 75.0 2.64 96.3
<br />0.98 26,070 158 55 25,030 615 2.13 96.0
<br />
<br />a (Weighl of food fed)/(weight of fish gained).
<br />b Pond received one treatmenl of alfalfa pellets al 100 Ib/acre.
<br />
<br />to 98.6% (Table I). Size of fish varied from 724
<br />to 508/1b.
<br />
<br />Sub fingerling Culture
<br />
<br />Subfingerlings were reared 51-70 d; water tem-
<br />perature varied from 61 to 7 SOF. Survival ranged
<br />from 92.7 to 95.8% (Table I). Size of sub finger-
<br />lings varied from 141 to 159/lb. The pond which
<br />had received a single treatment of alfalfa pellets
<br />prior to stocking supported the greatest survival
<br />(95.8%) but had the highest food conversion (2.67)
<br />of the three ponds.
<br />
<br />Fingerling Culture
<br />
<br />Fingerlings were reared 50-55 d; water temper-
<br />ature varied from 67 to 760F. Total survival was
<br />96.2% (Table I). Size offish varied from 61.5 to
<br />75.0/lb. Food conversion was 2.13 and 2.64 in the
<br />two ponds.
<br />Since the razorback sucker program was moved
<br />to Dexter National Fish Hatchery in 198 I, culture
<br />techniques have improved. From 1981 to 1984,
<br />survival of razorback suckers cultured from fry to
<br />fingerlings was 10.8, 14.1, 35.7, and 23.6%, re-
<br />spectively. Total survival during 1985 was 91.8%.
<br />Improvement in such pond management practices
<br />as fertilization rate and stocking rate has contrib-
<br />uted to better survival.
<br />The future of the razorback sucker may depend
<br />on hatchery propagation and culture to help re-
<br />store the species. In addition to providing speci-
<br />mens for restocking former habitats and supple-
<br />menting native populations, much is being learned
<br />about reproduction, early development, and re-
<br />
<br />quirements. This information may insure the sur-
<br />vival of the species.
<br />
<br />Acknowledgments
<br />1 thank Buddy Jensen, Troy Winham, Joe Ow-
<br />ens, Phillipe Sosa, and Sharon Coats for assistance
<br />during this study.
<br />
<br />References
<br />
<br />Deacon, J. E., G. Kobetich, J. D. Williams, and S. Con-
<br />treras. 1979. Fishes of North America endan-
<br />gered, threatened or of special concern: 1979. Fish-
<br />eries (Bethesda) 4(2):29-44.
<br />Hamman, R. L. 1985. Induced spawning of hatchery-
<br />reared razorback sucker. Progressive Fish-Culturist
<br />47:47-49.
<br />Inslee, T. D. 1982. Spawning and hatching of the ra-
<br />zorback sucker (Xyrauchen texanus). Proceedings of
<br />the Annual Conference Western Association ofFish
<br />and Wildlife Agencies 62:431-432.
<br />Johnson, J. E., and J. N. Rinne. 1982. The endangered
<br />species act and southwestern fishes. Fisheries (Be-
<br />thesda) 7(4):2-8.
<br />Marsh, P. C. 1985. Effect of incubation temperature
<br />on survival of embryos of native Colorado River
<br />fishes. Southwestern Naturalist 30:129-140.
<br />McAda, C. W., and R. S. Wydoski. 1980. The razor-
<br />back sucker, Xyrauchen texanus. in the upper Col-
<br />orado River basin, t 974---76. U.S. Fish and Wildlife
<br />Service Technical Paper 99.
<br />Minckley, W. L. 1973. Fishes of Arizona. Arizona
<br />Game and Fish Department, Phoenix.
<br />Minckley, W. L. 1983. Status of the razorback sucker,
<br />Xyrauchen texanus (Abbott), in the lower Colorado
<br />River basin. Southwestern Naturalist 28:165-187.
<br />Minckley, W. L., and E. S. Gustafson. 1983. Early
<br />development of the razorback sucker, Xyrauchen
<br />texanus (Abbott). Great Basin Naturalist 44:553-
<br />561.
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