3010 - Laserfiche WebLink

Home Browse Search

. 5. The tags were either weak, lost power~ or changed frequency so . they could not be readily picked up by the receivers. Nurrbers 1 and 2 above appear improbable. If the fish had died, or if the tags had fallen out, it seems highly unlikely that all of the signals would have . been lost. Also, the healthy appearance of two test squawfish, and the apparent health of 40.670, suggest that the surgical technique was satisfactory. Number 3 also does not appear likely as the fish released at Ouray would . have had to move over 250 miles to reach the Colorado River. All probable loca- tions in the Green River and its tributaries, the White, Duchesne~ and Yampa rivers, were searched. . Number 4 is feasible; data from Figure 3 show that in depths of 10 feet and greater, even strong tag signals probably would not be receivable at more than a few feet. This is compounded significantly with the use of the SR-40 scanning . receiver. Our knowledge of Colora.do squawfish habitat selection would suggest that it would be improbable that during high flows all six fish would remain in deep water. Also, even wh.en fish 40.670 was in water of 10 feet or more, here- . mai ned there for only a short whi 1 e. Therefore, the probabil ity that the six fish were not located due to residence in deep holes is very low. Equipment'failureappears to be the most likely explanation. Our testing . indicated weak signals, loss of power over time, and frequency changes. Ac- cording to the manufacturer, these problems should not have occurred. Also, the range of the .t gs should have been greater than observed. These transmitter . prob 1 ems, coup ed with the use of the SR-40 recei ver for mas t of the searchi ng, probably were he major cause for the inability to locate the six tagged fish. . 23 .