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6 of the ESA and by individual states, has pro- vided much of the basic information used to make decisions on efforts in behalf of the rare species. CODOW studies documented the im- portance of the Yampa River to the Colorado squawfish. The importance of the Green River to squawfish and humpback chub was verified by the UTDWR. Distribution of endangered Colorado River fishes in Cataract Canyon was examined by private contractors with USBR support (Valdez and Williams 1986; Valdez 1990). Culture and propagation techniques for rare Colorado River fishes were developed at Willow Beach (Arizona) and Dexter (New Mexico) national fish hatcheries (Hamman I982.a, et seq.: Inslee I982.a, b), Description of the larval stages of these fishes was com- pleted at Colorado State University by Muth (1988). San Juan River-The Forgotten Basin The San Juan River originates in the moun- tains of southwestern Colorado and flows South into Navajo Reservoir and then east through the deserts of New Mexico and Utah to eventually join the Colorado River in Lake Powell. Historically, the San Juan provided habitat for Colorado squawfish, razorback sucker, and perhaps bony tail, although histor- ical data indicate that none of these species was common. An effort to eradicate native and introduced rough fish before closing the Navajo Reservoir in the early I960s was de- scribed as effective, but only four large squaw- fish were documented as being killed by the treatment (Olson I962.a, b). A limited survey in the I970S resulted in the capture of a single juvenile Colorado squawfish near Aneth, Utah (VTN Consolidated 1978), Razorback suckers were rare, and records were based more on local testimony than on actual specimens (Minckley et a!., this volume, chap. 17), Fi- nally, the name "bony tail" was used for other Gila species, particularly roundtail chub (G. Evolution of a Recovery Program I 3 I robusta), SO the presence of bony tail in the San Juan remains questionable. Until recently the San Juan was relegated co a relatively low priority in upper-basin recov- ery efforts for endangered fishes. This low priority is mostly attributable to the 1979 USFWS biological opinion on the proposed Animas-La Plata Project, which concluded: "because of the apparent small size of the San Juan River squawfish population and its al- ready tenuous hold on survival, its possible loss will have little impact on the successfully reproducing Green and Colorado River squawfish populations and therefore on' ~e species itself." The opinion also concluded that construction of the Animas-La Plata Project would further change the San Juan River to a point where the Colorado squaw- fish population in the river would likely be lost. The Animas-La Plata biological opinion also recommended that the liSBR conduct a thorough study of the native fishes in the San Juan River. These studies were initiated by the states of Utah and New Mexico in 1987 under contract with the USBR. Salient findings of these studies (Platania and Young 1990) in- clude the following: (I) Colorado squawfish were collected from the San Juan River at sev- erallocations from Shiprock, New Mexico, to Lake Powell, Utah; (2.) successful reproduc- tion of Colorado squawfish was confirmed in 1987 and 1988 by the capture of eighteen young-of-year fish; and (3) suitable Colorado squawfish habitat appears present throughout the San Juan River, and this species appears to occupy the river on a year-round basis. As a result of these findings, the USBR rein- itiated section 7 consultation on the Animas- La Plata Project in early 1990. Based on re- sults of the San Juan fisheries surveys, and the belief that Colorado squawfish populations were not stable or were showing additional signs of decline in other pans of the upper basin, the USFWS issued a draft biological opin-