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Last modified
7/14/2009 5:02:29 PM
Creation date
5/20/2009 10:36:29 AM
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UCREFRP
UCREFRP Catalog Number
7048
Author
Desert Fishes Council (Edwin Pister, e.
Title
Proceedings of the Desert Fishes Council
USFW Year
1991.
USFW - Doc Type
Volumes XX and XXI
Copyright Material
NO
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All data on fish movement and habitat use were based on these 40 <br />radiotagged fish, although 1 Colorado squawfish and 3 razorback suckers were <br />excluded from the database for various reasons. None of the data associated <br />with Colorado squawfish OR-3237 were used, since the fate of the fish was <br />unknown; only the radiotransmitter was found on a dry sand bar. Of the three <br />razorback suckers excluded, no data were collected on GR-6110, since the <br />partially decomposed carcass with transmitter were found shortly after release; <br />the data associated with GR-129 were also not used, since this fish was <br />suspected of being a hybrid of a razorback and flannelmouth sucker (such <br />crosses have been reported, McAda 1978); OR-3230 was not contacted following <br />release, for the only suspected case of transmitter failure during this <br />investigation. <br />In year 2, we also recontacted 3 razorback suckers (GR-2417, GR-6117, OR- <br />3266) and 1 Colorado squawfish (GR-6104), which had been tagged during year 1; <br />all four fish were equipped with AVM transmitters that had surpassed their 12 <br />to 14-month life expectancy. We no longer received signals from the four <br />transmitters in March of year 2, and we concluded that these had functioned for <br />about 17 months. During monitoring, these fish appeared to behave normally, <br />and the data from razorback sucker GR-2417 and Colorado squawfish GR-6104 were <br />included in the year 2 database. Razorback sucker GR-6117 was contacted only <br />by aerial tracking, and was not monitored because the fish was located in a <br />relatively inaccessible area near mitten Park, while razorback sucker OR-3266 <br />was contacted too infrequently to monitor. <br />Capturing The Fish <br />All fish used in this investigation were captured with a 220-volt DC <br />electrofinding system, controlled by a Coffelt VVP-15 variable voltage <br />pulsator. The normal operating level was 90-200 volts and 4-10 amps, at 80 <br />pulses per second with a 40 percent pulse width. A 16-foot jonboat and an 18- <br />foot Havasu raft were equipped with electrofinhing systems which were removed <br />during tracking. <br />Electrofishing was conducted primarily along shorelines and other suitable <br />habitat accessible by boat. All adult Colorado squawfish and razorback suckers <br />were held in live wells for transport to a nearby mobile surgery station for <br />implanting the radiotransmitters. Other endangered fishes were weighed, <br />measured, tagged and released, including Colorado squawfish and razorback <br />suckers considered too small for surgical implant. No endangered humpback chub <br />(Gila cypha) or bonytail (Gila elegans) were captured during this study. <br />Radiotelmetry Equipment and Techniques <br />Radiotransmitters And Receivers <br />Of the 20 radiotransmitters used in year 1, 10 were manufactured by Smith- <br />Root (model P-40) and 10 by AVM (model SM-1). These transmitters were powered <br />by lithium and mercury batteries, respectively, each with a 12 to 14-month life <br />expectancy. For year 2, 20 Smith-Root (P-40) radiotransmitters were used. <br />These transmitters operated within the 40.660 to 40.700 MHz range, with <br />transmission rates of 40 to 80 pulses per minute. All transmitters were tested <br />for pulse and frequency upon receipt from the factory, and each was dipped in <br />melted beeswax prior to implantation to minimize negative reaction by the <br />30
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