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<br />274
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<br />
<br />FISH CULTURE IN FISHERIES MANAGEMENT
<br />
<br />A fourth species stocking from Dexter NFH
<br />occurred on November 9, 1981, when the FWS
<br />and AG&F stocked 45,000 bony tail (Gila elegans)
<br />into Lake Mohave to augment the only known
<br />pure population of that endangered fish species.
<br />Some 40,000 additional bony tails were stocked in
<br />Lake Mohave during th~ summer of 1982. Because
<br />of the lacustrine conditions in Lake Mohave,
<br />bony tail have survived there since the Colorado
<br />River was impounded by Davis Dam, in the early
<br />1950s, but have been unable to reproduce suc-
<br />cessfully. Stocking young bony tails in Lake Mo-
<br />have was an attempt to provide protection for the
<br />gene pool for another 30 years rather than to
<br />produce a viable reproducing population.
<br />Reasons for this changing view toward re-in-
<br />troducing both listed and unlisted native fish
<br />species into historic habitats are complex. Reasons
<br />include personal commitments from a few key
<br />individuals, increased public interest in native
<br />species, a more reliable funding source for non-
<br />game projects, and willingness of several agencies
<br />to look beyond minor near-term problems to the
<br />future of natural aquatic ecosystems within their
<br />jurisdictions. Two other points should be made
<br />concerning re-introduction. For several years, a
<br />number of groups have recommended the ESA
<br />be amended to alter the strict regulations that
<br />hinder re-introduction efforts. The ESA was re-
<br />authorized in 1982, and, after hearing numerous
<br />comments from the public, Congress amended
<br />Section 10 of the Act to allow for a new category
<br />("experimental"), designed to expedite re-intro-
<br />duction actions.
<br />In concept, the experimental category was de-
<br />signed to remove most federal regulations pro-
<br />tecting re-introduced populations and give regu-
<br />latory authority for those populations back to the
<br />states. Wild populations would retain their present
<br />listing designation. Without the restraint of ex-
<br />tensive federa\ protective measures and regula-
<br />tions, it is foreseeable that there could be important
<br />new stockings of endangered fish species in the
<br />Southwest under the experimental category. Such
<br />actions could mark the beginning of a major
<br />reversal in the declining' trend for native fish species
<br />in this region. If this method of recovery succeeds,
<br />and Dexter NFH plays an important p3;rt in the
<br />action, the FWS is likely to consider authorizing
<br />similar facilities in other parts of the country. In
<br />practice, regulations finalized in 1984 to designate
<br />experimental populations were so unwieldy that
<br />it became more difficult to remove the federal
<br />ties for a re-introduced population than it was to
<br />
<br />list the species in the first place. This failure of a
<br />good idea to materialize into a workable action
<br />will certainly slow down the re-introduction effort
<br />and make production planning at Dexter NFH
<br />more difficult.
<br />The second point to keep in mind is that, in
<br />most cases, re-introduction of endangered species,
<br />into habitats from which they have been extir-
<br />pated, is a stop-gap measure toward recovery.
<br />Habitat loss is the principle factor in decline of
<br />the native southwestern fish fauna, and the only
<br />sure method of its recovery is. identification and
<br />protection of selected waters. While re-introduc-
<br />tion may be able to reverse the current downward
<br />trend in native fish species, habitat protection.
<br />should be considered the primary recovery action.
<br />I ..
<br />
<br />Operation of an Endangered-Fishes Facility
<br />
<br />Rivers and springs of the American Southwest
<br />and their fish fauna have changed dramatically
<br />during the 20th century, primarily due to con-
<br />struction of dams, pumping of ground water,
<br />grazing of range lands, and introduction of non-
<br />native fishes. Habitats have also been altered by
<br />soil erosion and deposition due to poor land
<br />management practices, and by transplanted fishes
<br />that prey on native fish species and compete with
<br />them for available habitat and food resources.
<br />These activities have resulted in a continuous and
<br />progressive reduction in the distribution and abun-
<br />dance of the unique endemic ichthyofauna of the
<br />region (Johnson and Rinne 1982). In 1974,' fol-
<br />lowing passage of the ESA, Dexter NFH began
<br />working with endangered southwestern fishes to
<br />determine whether they cotYd b~ held and reared
<br />in captivity. This facility is now totally engaged
<br />in holding, culturing, and distributing many of
<br />these imperiled fishes. ~ ~ i' ':1;, :,'
<br />
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<br />Facility Description 1.,1. '.
<br />
<br />Dexter NFH is located in the Pecos River Valley
<br />of southeastern New Mexico. Elevation is 3,500 I .
<br />ft, average annual rainfall about 12 inches, and
<br />the growing season 180 to 200 days. Water is
<br />supplied by three shallow wells, is slightly alkaline
<br />(pH 7.2 to 7.5), and temperature is a constant
<br />64 F. Total hardness averages 2,100 ppm and total
<br />.t~,,'_-,]I /-,
<br />dissolved solids approximately 3,500 ppm,"""
<br />Culture facilities at Dexter consist of a holding
<br />house (with sixteen 35o-gal tanks, a' hatching
<br />battery, and laboratory) and 48 earthen ponds.
<br />Ponds vary from 0.1 to 1.8 acres, comprising ai
<br />total of 20.8 acres. Waste water is imPo.unded on'
<br />. , ,'14' li't1q~If,>.'.i ';
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