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1 1 YOY Colorado squawfish. However, if Haines and Tyus's observations are upheld with ' ISMP data, refining the selection of sampling sites or consideration of the physical parameters of backwaters in calculation of CPE will probably not increase the precision of ' relative-abundance estimates. Analyses of these data are being done in a separate report. Bates et al. (1991) reviewed part of the data reported here and found a slight, but not significant, positive relationship between backwater temperature and CPE of YOY Colorado ' squawfish. ISMP sampling protocol already requires that seining not begin until backwaters have warmed (at least a little) from the previous night's low temperature. It is unlikely that ' water temperature and its effect on CPE can be addressed any further by more a restrictive sampling protocol. L 1 7 j UDWR is presently conducting a more detailed study of Colorado squawfish nursery habitat in 10-mile subreaches within ISMP reaches. The study expands on work done by Haines and Tyus (1990) and involves much more intensive sampling within the 10-mile subreaches than occurs under ISMP. Aerial-video mapping of backwaters and other habitats within the 10-mile subreach is an important part of this investigation. The study is designed to elaborate on what is known about preferred habitat and to determine how much of this 'preference' can be identified from aerial video. The video interpreter works very closely with the investigators conducting the field work. Small scale studies such as this are better suited to using aerial video than studies requiring interpretation of 320 miles of river. The video interpreter can work closely with biologists on the river to improve consistency between field and video interpretations. Close cooperation with people on the river is impossible when most of the river is being photographed and interpreted. The short river reaches being studied also ensure that both video collection and YOY Colorado squawfish sampling are done at the same flows. If the Nursery Habitat study identifies aspects of preferred habitat that can be measured from the air and will improve CPE as an index of relative abundance, aerial video can be reincorporated into the monitoring program. In the interim, video can still be collected at reasonable cost since the helicopter will be in the ISMP reaches anyway collecting video for the Nursery Habitat study. However, funds can be saved by delaying interpretation until such time as additional variables are identified and video interpretation can provide additional information. Video was flown in fall of 1992 during collection of ISMP fish data. Interpretation of this data could provide an additional year of the type of data evaluated here. Quick interpretation would provide a fourth year of data to assist with this evaluation. However, because of concerns mentioned above, interpretation of the 1992 video should wait until 19