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., <br />Dispersal of and predation on stocked, fingerling razorback <br />sucker was evaluated in the Gila- River near Clifton, Arizona <br />during September 1985. Methods were similar to those described <br />by Brooks and Marsh (1985) and Brooks et al. (In prep.) with some <br />modification. Dispersal was monitored by hoop nets placed 0.5 km <br />upstream and 0.5, 1.0, 1.5 and 2.5 km downstream of the stocking <br />site and seining in various habitats. Amore intensive predation <br />evaluation was conducted in 1985 (Marsh In prep.) to confirm 1984 <br />results that stocked razorback sucker were consumed at <br />significant rates by introduced ictalurids (Brooks and Marsh <br />1985, Brooks et al. In prep.). <br />Prior to stocking, a multiple mark-recapture population <br />estimate was made for channel (Ictalurus punctatus) and flathead <br />(Pylodictis olivaris) catfish in a 2.0 km reach encompassing the <br />stocking site. Sampled surface area was estimated and general <br />habitat observations recorded. After stocking, all catfish taken <br />were immediately killed, measured, and weighed. Intact digestive <br />tracts were removed and preserved for later analysis. Population <br />estimation followed methods of Schumaker and Eschymeyer (Gerking <br />1953, kicker 1975) for numbers of channel catfish > 150 mm <br />Standard Length (SL) and flathead catfish ~ lU0 mm SL, <br />approximate minimum lengths at which razorback sucker were <br />consumed (see below). Catfish stomach contents were examined and <br />consumed razorback sucker enumerated and standard lengths <br />compared to stocked fish and predator lengths. Consumption rates <br />and population estimates were combined to assess impact on <br />stocked fish numbers. <br />-4- <br />