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<br />
<br />28
<br />
<br />COMMUNrCA TrONs
<br />
<br />TABLE 2. -Survival of Colorado squawfish fry and fingerlings in earthen ponds during 1987 at Dexter National
<br />Fish Hatchery, New Mexico.
<br />
<br />Johnson, J. E.,
<br />species ac
<br />thesda) 7 (
<br />Joseph, T. W.
<br />Holden.
<br />history, ar
<br />threatene(
<br />tern. U.S.
<br />and Land
<br />Marsh, P. C.
<br />on surviv
<br />fishes. SOl
<br />Minckley, W.
<br />Game anc
<br />
<br />Pond size Stocking Days in Recovery Food Percen t
<br />(acres) Number of /ish Size (/ish/lb) pond Number of /ish Size (/ish/lb) conversion3 survival
<br /> Fry
<br />0.95 100,050 104,420 48 27,720 1,115 27.7
<br />0.89 122,320 95,340 49 42,558 1,038 34.8
<br />0.98 115,250 103,512 51 41,538 966 36.0
<br /> Fingerlings
<br />1.08 59,858 1,088 86 51,360 240 4.89 85.8
<br />0.98 51,918 980 90 51,750 230 4.83 99.7
<br />
<br />a Weight of food fed/weight of /ish gained.
<br />
<br />Fry were also fed a commercial trout starter diet
<br />beginning on day 1. Feeding rate was not calcu-
<br />lated because the formulated feed was a supple-
<br />ment to the natural plankton (rotifers and cladoc-
<br />erans) present in the ponds.
<br />One problem organism was encountered in the
<br />three ponds 3-4 d before fry were stocked. Ponds
<br />developed an excessive turbidity resulting from
<br />clam shrimp (Cyzicus sp.). This crustacean was
<br />easily controlled by the insecticide Masoten@ (tri-
<br />chlorfon) applied at the rate of 0.25 ppm (Piper
<br />et al. 1982); however, plankton populations were
<br />affected and probably attributed to the low percent
<br />survival of this group of fish.
<br />Fingerling culture. -Fingerlings (111,776) were
<br />stocked in two 0.98-1.08-acre earthen ponds of
<br />3-ft average depths. Stocking densities were
<br />52,978-55,424 fingerlings/acre. At stocking, the
<br />fingerlings ranged from 980 to 1,088/1b between
<br />the two ponds. Fish were fed a commercial trout
<br />diet (number 1 and 2 granules) at 5.0% of body
<br />weight daily beginning the day they were stocked.
<br />
<br />Results and Discussion
<br />
<br />Fry Culture
<br />
<br />Fry were reared 48-51 d; water temperature
<br />varied from 67 to 750F. Survival ranged from 27.7
<br />to 36.0% (Table 2). Size of fish varied from 966
<br />to 1,155 fish/lb.
<br />
<br />Fingerling Culture
<br />
<br />Fingerlings were reared 86-90 d; water temper-
<br />ature varied from 64 to 770F. Total survival was
<br />92.2% (Table 2). Size of fish varied from 230 to
<br />240 fish/lb. Food conversion (weight of feed fed!
<br />weight gained by fish) was 4.83 and 4.89 in the
<br />two ponds.
<br />The low survival of Colorado squawfish fry (Ta-
<br />ble 2) was probably due to the depleted zooplank-
<br />ton population in the ponds at stocking time. Clam
<br />
<br />shrimp will compete with fry for food and cause
<br />excessive turbidity that interferes with photosyn-
<br />thesis. They offer no value to fry as fish food be-
<br />cause of their hard external shell and fast growth
<br />to sizes too large for consumption (Piper et al.
<br />1982). Treatment procedures during pond flood-
<br />ing may prevent this eubranchiopod from repopu-
<br />lating the pond before the critical period of plank-
<br />ton growth commences.
<br />The future of the Colorado squawfish will prob-
<br />ably depend upon hatchery efforts to restore the
<br />species. The cultural progress made so far suggests
<br />we may be able to help the Colorado squawfish
<br />again inhabit its historic habitats in the Colorado
<br />River basin and insure the survival of this endan-
<br />gered fish species.
<br />
<br />The Progressive Fis
<br />
<br />ELI
<br />
<br />Division 0)
<br />oS
<br />
<br />c
<br />
<br />Acknowledgments
<br />
<br />I thank Buddy Jensen, Troy Winham, Joe Ow-
<br />ens, Phillipe Sosa, and Sharon Coats for assistance
<br />during this study.
<br />
<br />Abstract. -Ii
<br />dure develope(
<br />od instead to i
<br />largemouth ba~
<br />its effectivenes
<br />Effectiveness 0
<br />of a control tre
<br />antibiotic. The
<br />d following ba;
<br />treatment) was
<br />of fish in eith(
<br />groups. Altho~
<br />higher than the
<br />ference was not
<br />of HI in the ad
<br />improved throl
<br />chemical surfa(
<br />
<br />References
<br />
<br />Behnke, R. J., and D. E. Benson. 1980. Endangered
<br />and threatened fishes of the upper Colorado River
<br />basin. Colorado State University, Cooperative Ex-
<br />tension Service Bulletin S03A, Fort Collins.
<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. 1981. Spawning and culture of Col-
<br />orado squawfish in raceways. Progressive Fish-Cul-
<br />turist 43:173-177.
<br />Hamman, R. L. 1986. Induced spawning of hatchery-
<br />reared Colorado squawfish. Progressive Fish-Cul-
<br />turist 48:72-74.
<br />Holden, P. B., and E. J. Wick. 1982. Life history and
<br />prospects for recovery of Colorado squawfish. Pages
<br />98-108 in W. H. Miller, H. M. Tyus, and C. A.
<br />Carlson, editors. Fishes of the upper Colorado Riv-
<br />er system: present and future. American Fisheries
<br />Society, Western Division, Bethesda, Maryland.
<br />
<br />Many anti!:
<br />oxytetracyclir
<br />to control or .
<br />tibiotics are cc
<br />of three ways:
<br />
<br />I Present ad!
<br />of Wisconsin, ]
<br />
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