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3.) Remove nonnative fish species which prey upon and compete with native fish species in the San Juan River. I I I I I I I I I I I I continue to be done on adult monitoring trips. The study design for adult monitoring is based upon the criteria for long..term monitoring of the San Juan River main channel fish community. These criteria were accepted as final by the San Juan River Biology Committee on 31 March 2000. Description of Studv Are~,: The study area for adult monitoring extends from river mile (RM) 180.0 (Animas River confluence) in Farmington, New Mexico, downstream to RM 2.9 (Clay Hills Landing) just above Lake Powell in Utah. The entire reach of river from RM 180.0 to RM 2.9 will be sampled in the fall of every year (sampling to begin in the second to third week of September). Obiectives: L) Monitor the San Juan River's main channel fish community, specifically the large-bodied fish species, to identifY Hhifts in fish community structure, species abundance and distribution, and length/weight frequencies that are occurring corresponding to management actions that are being implemented by the San Juan River Recovery Implementation Program. These include (but may not be limited to) tht: following: a) reoperation of water releases from Navajo Reservoir b) mechanical removal of nonnative fishes c) modification or removal of instream water diversion structures d) augmentation efforts for both federally-listed endangered fish species - Colorado pikeminnow and razorback sucker 2.) Monitor populati.on trends (e.g., distribution and abundance, habitat use, spawning and staging areas, growth rates, recruitment) of the rare San Juan River fish species - Colorado pikeminnow, razorback sucker, and roundtail chub (both wild and stocked fish). Methods: 2 Objectives 1-3: One adult monitoring trip will take place in fall 2005. This trip will sample from the Animas River confluence in New Mexico (RM 180.0) to Clay Hills Landing in Utah (RM 2.9). Electrofishing will be the primary sampling technique, although seining and trammel netting may also be employed. Two oar-powered rafts, 'ovith one netter each, will electro fish in a continuous downstream fashion, with one raft on each shoreline. No outboard motors will be used. Sampling crews will consist of approximately 8-9 people (4 for electrofishing, 2 for baggage rafts, and 2-3 for other research elements that are being done simultaneously with our sampling). Electrofishing will sample two out of every three miles (approximately 120 total sampled miles). All fish collected will be enumerated by species md life stage every sampled mile. Every fifth sampled mile (known as a "designated mile" or DM), all fish collected will be weighed and measured. All native fish collected will be returned alive to the river. All nonnative fish collected will be removed from the river. All nonnative pr,~datory fishes (i.e. - walleye. striped bass, largemouth bass. smallmouth bass) collected will be weighed, measured, and have stomach contents taken, before being removed from the river. Tag numbers, total length, and weight will be recorded on all recaptured, FLOY - tagged fish (both native and nonnative), as well as any rare fish collected. Colorado