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• 1997 Paria River Native Fish Monitoring .Introduction Use of the Paria River, Arizona, by spawning flannelmouth suckers (Catostomus latrpinnis) has been well documented. Suttkus and Clemmer (1976), Carothers and Hinckley (1981), Maddux et al: (1987), Brouder and Hoffrtagle (1997) and Thieme (in preparation) reported ripe flannelmouth suckers near the confluence of the Paria and Colorado Rivers and spawning in the Paria River. Weiss (1993) reported flannelmouth sucker spawning activity and young-of--year (YOY) in the lower 10 kilometers (km) of the Paria River. Arizona Game and Fish Department (AGFD) caught 441arval flannehnouth suckers caught during 13 May, and 15 June 1994, verifying successful spawning. On 15 June 1994, 297 juvenile flannelmouth suckers were • captured, ranging in length from 30 - 50 mm total length (TL). In 1996, AGFD, in conjunction with the University of Arizona, monitored use of the Paris River by native fishes and reported high recruitment by flannelmouth sucker and speckled dace (Rhinichthys osculus). This high recruitment may be attributed to: 1) a lack of significant flooding in the Paria River during periods of high larval and YOY prevalence and/or 2) high mainstem Colorado River flows which ponded the mouth of the Paris River, creating a slackwater rearing habitat. Conditions were very good for rearing and ultimately recruitment of flannelmouth sucker in 1996. In addition to successful recnutment in 1996, AGFD reported post-spawn mortality of adult flannelmouth suckers. This is the first known record of such an occurrence by spawning adult flannelmouth sucker in the Paria River. This report summarizes results of monitoring the use of the Paria River by native fishes in 1997. Based on findings in 1996, we continued to examine post-spawn mortality of spawning adult flannelmouth suckers, recruitment of flannehnouth sucker and speckled dace and factors affecting recruitment (e.g., Paria River discharge, Colorado River discharge and rearing habitat • availability). Study Site Ten standardized AGFD sites were sampled in the lower 4.8 km of the Paria River (Table 1; Figure 1). Of these, nine were classified as runs, while Site 10, located at the confluence of the Paria and Colorado Rivers, was classified as pool habitat. Locations of sampling sites are noted as river kilometer (RK) upstream from the mouth. Brouder and HoBnagle, 1997 Annual Report Arizona Game & Fish Department. 1 •