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<br />ciliidae; the entire world population at one time consisted
<br />of two males and one female; Hubbs and Brodrick 1963).
<br />This does not imply that recovery efforts will fail and should
<br />be abandoned, but rather that the best approximation to ge-
<br />netic guidelines possible under individual circumstances
<br />should be made. This paper is intended solely as a guide to
<br />sound genetic management; principles and suggestions
<br />should not be considered "absolute," and endangered spe-
<br />cies programs should not be abandoned if the guidelines
<br />herein cannot be rigorously met.
<br />The models outlined in this paper are based on current,
<br />and certainly incomplete understandings of genetics of small
<br />populations and may not be entirely applicable to some
<br />species. For example, the Devil's Hole pupfish (Cyprinodon
<br />diabolis, Cyprinodontidae) has apparently existed for thou-
<br />sands of generations with populations hovering near several
<br />hundred individuals (Miller 1948). Classical genetic models
<br />predict that continual inbreeding s'.lould probably have al-
<br />ready led to extinction of this species, yet it still thrives in
<br />its single locality. The point here is that, although our cur-
<br />rent knowledge of conservation genetics is incomplete and
<br />perhaps inaccurate in some cases, it is the best information
<br />presently available. Even if strict adherence to these basic
<br />principles proves unnecessary in particular cases, it is a con-
<br />servative approach to species maintenance since it inevitably
<br />maximizes remaining genetic variation. The fa" k of endan-
<br />gered species maintenance in perpetuity is admittedly diffi-
<br />cult but there are few alternatives if we wish to conserve
<br />fishes for more than a few generations. The genetic dangers
<br />faced by any small population appear to be great; the costs
<br />of ignoring this fact may be even greater.
<br />Acknowledgments
<br />I thank D. A. Hendrickson, J. E. Johnson, W. L. Minckley,
<br />J. G. Robinson, and R. C. Vrijenhoek for discussion and
<br />critical reviews of earlier drafts, and G. Kiltie for typing the
<br />manuscript. Financial support was provided by the De-
<br />partments of Zoology at Arizona State University and the
<br />University of Florida and by contract DE-AC09-76SR00-819
<br />between the U.S. Department of Energy and the Institute
<br />of Ecology of the University of Georgia. This paper is ded-
<br />icated to the outstanding group of American and Mexican
<br />biologists committed to saving endangered North American
<br />fishes.
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