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squawfish <br />2. Determine whether the few adults presently in <br />captivity can identify their natal waters (Willow Beach <br />National Fish Hatchery) by smell <br />3. Determine if Colorado squawfish fry can <br />be imprinted by exposure to an artificial chemical and <br />retain the information from the chemical until sexually <br />mature <br />Test fish <br />The Utah Cooperative Fishery Research Unit presently holds <br />about 25 adult squawfish and several hundred juveniles of various <br />age classes. Several dozen adults are held at Dexter National <br />Fish Hatchery and wild adults can occasionally be obtained by <br />personnel from Fish and Wildlife Service field offices in Vernal, <br />Utah and Grand Junction, Colorado. <br />METHODS <br />An electroencephalographic (EEG) technique can be used as -a <br />method to determine olfactory acuity and as a bioassay for home <br />stream recognition (Hara 19700, Cooper and Hasler 1970. A portion <br />of the skull of a live, but paralized and restrained, fish is <br />removed with a dental drill to permit the insertion of an <br />electrode into the olfactory bulb. The EEG recordings are made <br />on a polygraph as test solutions are introduced through a pipette <br />to the nares. Basal EEG's have a consistant, synchronous pattern <br />of low amplitude (about 100 uV).; recognized chemicals induce a <br />wave pattern of higher amplitude (Hara 1971). <br />Initial studies to refine surgical techniques will be <br />2