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1979 THE ENDANGERED SPECIES: A SYMPOSIUM A. I consider 200 pupfish to be one which puts the spe- cies in approximately the position it was prior to the appearance of man-not completely in that position, but approximately. Now it's as threatened as it al- ways was because of its restricted habitat, but it is no more threatened because of man's activities. Q. Would cleaning up the waters here in the West af- fect the species population? A. In those areas where pollution is a problem it cer- tainly would. Almost anything that's proposed which will modify habitats must be examined with respect to the possibilities of adversely affecting species, whether or not they are endangered. It doesn't nec- essarily mean that, for instance, salinity control pro- jects will affect the woundfin minnow. In fact, some of my work has demonstrated that there is probably a good opportunity to design salinity control projects that will be unlikely to affect the mainstream fishes of the Virgin River. That conclusion is expandable to many other instances in the Southwest. The impor- tant thing is to design projects that are compatible with the habitat requirements of the species im- pacted. In other words, cleaning up the waters of the West could affect species in a number of ways, both adversely and favorably. Q. I'm not convinced that what you have said about the proposal to not go ahead with the power plant in Dixie is reasonable. The suggestion was that they di- vert some of the water from the Virgin River into a reservoir in Warner Valley and with that carry on with their electrical work. Now, of course, it would be a coal plant and this would be cooling water for the hydro plant. What is the problem? How is it go- ing to endanger that fish? A. The question is how is the Warner Valley Project Iikelv to add to the threats to the woundfin minnow and'roundtail chub in the mainstream Virgin River. Thanks very much for asking it, Vasco (Tanner). This obviously is not a simple problem. The basic answer I see is that the Warner Valley Project as projected will alter the flows of the mainstream Virgin River. The hydrologists point out that most of the water will be taken during the winter and spring. Data I presented here today indicate that during the low- flow winter, spring, and summer of 1977, woundfin and roundtail chub reproduction was extremely low. To the extent that the Warner Valley Project in- creases the frequency with which flows similar to 1977 occur, that project will adversely impact the endangered fishes living there. Essentially, the prob- lem is that the data so far demonstrate that 1977, which was a low-flow year, resulted in conditions in- compatible with very much reproduction of those two species. If you cut off that reproduction, you're likely to cause an extinction. Certainly ev~ry time you modify the flow regime of the Virgin River such that the native fish populations living there miss a year of reproduction, you're very demonstratively af- fecting the capability of those species to maintain themselves in the river. My conclusions here are really based on the fact that we have demonstrated very poor reproduction during a time which repre- sents the kind of postproject flows we could expect. Q. Of course I've seen that river fluctuate from great to almost nothing, so naturally I don't see that there is any justification for not going ahead with it. They're going to get water from Warner Valley as well as just divert a little from the Virgin River into the res- ervoir. A. The crux of the matter, I think, is what flows are necessary to permit reproduction of the woundfin minnow. The data I presented suggest that flows in the neighborhood of 100 cubic feet per second are necessary to permit reproduction of woundfin and roundtail chub. In fact, there is some suggestion that winter flows must be somewhat higher. If the Warn- er Valley project doesn't reduce winter and spring flows below about 110 cubic feet per second, then I would say that there is likely to be no adverse im- pact. On the other hand, if it does, and it was dem- onstrated by the hydrological study that it would, then it does represent an impact. I'm not saying you shouldn't have the project. All I am saying is, if you reduce flows, you're going to impact the minnow and the chub. Q. Just a comment more than a question. I understand the Warner Project during 1977 would not have been allowed to divert because the water was so low that project requirements would not have permited diversion. The 1977 situation would not be repeated unless there was another low-water year. A. If that's the case, then I fail to see the basis for the rather marked objections that have been raised to the conclusions I have reached. LITERATURE CITED CLEMENT, D. A. 1979. Rare species and culture. Great Basin Nat. Mem. 3:11-16. COTIAM, W. P. 1961. Our renewable wild lands-a chal- lenge. Univ. Utah Press, Salt Lake. CROSS, J. N. 1975. Ecological distribution of the fishes of the Virgin River (Utah, Arizona, Nevada). Un- published thesis. Univ. Nevada, Las Vegas. _' 1978. Status and ecology of the Virgin River Roundtail Chub, Gila robusta seminuda (Os- teichthyes:Cyprinidae). S.W. Nat. 23(3): 519-528. DEACON, J. E., AND M. S. DEACON. 1979. Research on endangered fishes in the national parks with spe- cial emphasis on the Devils Hole pupfish. Proc. First Conf. on Scientific Research in the National Parks. Vol. 1:9-20. DEACON, J. E., C. HUBBS, AND B. J. ZAHURANEC. 1964. Some effects of introduced fishes on the native fish fauna of southern Nevada. Copeia. 1964(2):384--388. DEACON, J. E., G. KOBETICH, J. D. WILLIAMS, AND S. CONTRERAS. 1979. Fishes of North America, en- dangered, threatened or of special concern: 1979. Fisheries 4(2):29-44. DEACON, J. E., AND W. L. MINCKLEY. 1974. Desert fish- es, pp. 385-487. In: Desert Biology, Vol. 2, Aca- demic Press, N.Y. fuSTlNGS, J. R., AND R. TURNER. 1965. The changing mile. Univ. Arizona Press, Tucson. HUBBS, C., AND J. E. DEACON. 1964. Additional in- troductions of tropical fishes into southern Ne- vada. S.W. Nat. 9(4):249-251. 63