7610 - Laserfiche WebLink

Home Browse Search

r 29 long term data set. If it was a short term observation the error would only, be a small part of the total data base. If the observer disturbs the fish upon approach, then short term observations might be recording the fish's use of "escape" type habitat as the fish reacts to or avoids the observer. Long term observations would allow the fish to settle into its normal behavior after the observer becomes less noticeable. The fish in the backwater at RMI 95.7 would often be moving as contact was established, but they would settle down after about 30 minutes and remain in frequently used areas for long periods. Sound and vibration of the approaching truck might have transferred through the frozen ground to the water startling the fish and causing them to move. Short term velocities had higher maximum velocities than those observed in long term observations (Table 12). Substrates measured during short term observations indicated the use of sand as compared to gravel which was used during long term observations. Fish used run habitat more in short term than in long term observations. These differences could be interpreted as observer influence on the fish. Long term observations are much harder to perform due to extreme low temperatures at night and the difficulty of collecting good data for 24 continuous hours. RECOMMENDATIONS AND CONCERNS 1. Due to the influence of ice on the flow patterns in the upper Yampa a annl it•ahi 1 i+.. .,f _ determination should be made regarding the I-&lf?and PHABSIM? procedures to winter habitat analvsis. Transect data which were taken near a Gk hydrologic control for the Government Bridge IF1M site should be evaluated to make the above determination. If W-Hrons not applicable, then other methods of evaluating habitat and making flow recommendations should be explored. 2. Consideration should be given to evaluating the availibi 'ty of winter habitat in and adjacent to the study areas. Some indication of habitat preference could then be determined. 3. Since there appears to be very little difference in the data collected in the morning, afternoon, evening, and night we suggest only shor` t term daft be collected during daylight and evening hours. 4. A standard method of evaluating substrate in the field and in data analysis should be adopted for both primary and secondary substrate combinations. 5. All potential fish locations should be approached with care to avoid 40 startling the fish. After making initial contact fish should be observed for 30 minutes to 1 hour before beginning the collection of data for microhabitat purposes. a D