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consisted of two aerial antenna arrays: one four-element and one nine-element directional antenna. <br />The canal station consisted of one four-element directional, aerial antenna and an underwater <br />antennae. The ideal location for installing this tracking station was on the south bank of the canal <br />because the single aerial antenna array could be directed at radio-tagged fish moving only in the <br />canal and not in the Colorado River. At this point, the Colorado River and canal paralleled each <br />other and were only about 200 m apart. However, the tracking station would interfere with <br />access and operations with personnel from the Grand Valley Water Users. Therefore, <br />authorization was granted to install the tracking station on the north bank of the canal. Because <br />the Colorado River and canal were close to each other, the directional aerial antennae could <br />detect signals from radio-tagged fish in both the river and canal. This presented a dilemma. <br />Using additional aerial antennas still would not allow researchers to determine if aradio-tagged <br />fish was moving in the canal or river. The solution was to use an underwater antennae. The <br />position of the underwater antennae would detect and record the signal ofradio-tagged fish <br />moving only in the canal, but not those in the adjacent Colorado River. <br />Data collected by the fixed, semi-permanent, land-based telemetry stations were <br />automatically stored in an internal memory in the receiver and were downloaded monthly to a <br />notebook computer. The data stored for each signal by the receiver included the following: <br />1. date, <br />2. time (h/min/sec), <br />3. channel or frequency, <br />4. power level of signal, <br />5. antenna. (combined, individual), and <br />6. signal code. <br />Data downloaded to the notebook computer were in ASCII.TXT format which were then <br />processed, edited, and converted to database files for manipulation and analyses. Telemetry data <br />were collected through 4 September 2002 by all three of the land-based receivers. <br />The other SRX 400 receiver (version 4.01/WSA), was not programmed for data logging, <br />and was used to search for radio-tagged fish from boats and vehicles between and outside the <br />range of the fixed, land-based stations. An aluminum boat (4.9 m in length) with a 65-horsepower <br />jet drive facilitated up- and downstream travel to monitor movements oftransmitter-tagged fish <br />following release. River reaches were searched for radio-tagged fish at least weekly between the <br />time fish were implanted with transmitters (June and the first of August in both 2000 and 2001), <br />and more frequently during the spawning season (see Appendix D for a summary of tracking <br />11 <br />