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8 According to Conway, the most recent report of squawfish from New Mexico was from the San Juan River near Bloomfield in 1965. But Parrish stated that the species is currently suspected to be in the San Juan River and its tributaries in northwestern New Mexico, and cited the most recent known occurrence to be near Cast1erock, New Mexico, in the San Juan River in 1965 as verified by New Mexico Game and Fish personnel. In April 1978, Minck1ey captured a I77-mm, 36-g squawfish near Aneth, Utah. The fish was captured in the Four Corners Region, just below the confluence of McE1mo Creek. This catch is significant because it is the only record of a squawfish from the San Juan River proper since 1965. The fish was caught among carp and red shiners (Notroois 1utrensis) in water 0.7- to 1.0-m deep. The size of the fish is evidence of recent reproduction in the San Juan River since it seems unlikely that a fish of that size would move upstream from Lake Powell and even more unlikely that spawning occurred in the reservoir. Perhaps most notable of historical accounts is Koster's report of 5- to 10-1b Colorado squawfish as "fairly common" in New Mexico with individuals reaching weights of 25 to 30 lb. Colorado squawfish are large, long-lived fish and specimens of this size indicate they were quite old and likely had inhabited the San Juan River for many years. More recent captures of Colorado squawfish throughout the entire Upper Basin yielded a few specimens of only 14 lb that were estimated to be approximately 15 years old (Chuck McAda, Colorado River Fishery Project, Grand Junction, Personal Communication). Also notable is the capture of adult male and female Colorado squawfish from the same pool of the San Juan River approximately 3 miles below the town of Rosa, New Mexico, They were both captured during the period normally associated with migration and spawning, suggesting a historical spawning run as far upstream as River Mile (RM) 267. Platania and Young (1989) summarized historical fish collections in the San Juan River drainage, confirming that Colorado squawfish once inhabited reaches above what is now the Navajo Dam an~ Reservoir near Rosa, New Mexico, at RM 270. In 1961, the New Mexico Department of Game and Fish conducted a preimpoundment fishery study within the area tD be inundated by the Navajo Reservoir in New Mexico. Olson (1962a) reported a predominance of nongame species with fathead minnow, f1anne1mouth sucker, b1uehead sucker, and roundtai1 chub the most numerous. Olson also reported the collection of four specimens of Colorado squawfish. Coincident with the preimpoundment study in September 1961, the San Juan River and tributaries upstream from the Navajo Dam were treated with rotenone to eliminate "trash fish" (Olson 1962b). Approximately 70 miles of the San Juan River, 15 miles of the Pine River (Los Pinos), and 6 miles of the Navajo River were treated, Olson (1962b) reported extensive fish kills in all three rivers, especially the San Juan River, where lethal concentrations of rotenone carried approximately 40 miles below the Navajo Dam site to near Fruitland, New Mexico, Olson reported a total of 14 different species collected, including Colorado squawfish; however, because of the project size, it was impossible to determine total numbers or weight of fish killed. It is important to note that the eradication project was accomplished long before the passage of the Endangered Species Act and/or the subsequent listing of rare native fishes throughout the Upper Basin,